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Bone marrow-derived stem cells (BMDSCs) play an essential role in organ repair and regeneration. The molecular mechanisms by which hormones control BMDSCs proliferation and differentiation are unclear. Our aim in this study was to investigate how a lack of ovarian or/and thyroid hormones affects stem cell number in bone marrow lineage. To examine the effect of thyroid or/and ovarian hormones on the proliferative activity of BMDSCs, we removed the thyroid or/and the ovaries of adult female rats. An absence of ovarian and thyroid hormones was confirmed by Pap staining and Thyroid Stimulating Hormone (TSH) measurement, respectively. To obtain the stem cells from the bone marrow, we punctured the iliac crest, and aspirated and isolated cells by using a density gradient. Specific markers were used by cytometry to identify the different BMDSCs types: endothelial progenitor cells (EPCs), precursor B cells/pro-B cells, and mesenchymal stem cells (MSCs). Interestingly, our results showed that hypothyroidism caused a significant increase in the percentage of EPCs, whereas a lack of ovarian hormones significantly increased the precursor B cells/pro-B cells. Moreover, the removal of both glands led to increased MSCs. In conclusion, both ovarian and thyroid hormones appear to have key and diverse roles in regulating the proliferation of cells populations of the bone marrow.

Biological scaffolds have become an attractive approach for repairing the infarcted myocardium and have been shown to facilitate constructive remodeling in injured tissues. This study aimed to investigate the possible utilization of bacterial cellulose (BC) membrane patches containing cocultured cells to limit myocardial postinfarction pathology. Myocardial infarction (MI) was induced by ligating the left anterior descending coronary artery in 45 Wistar rats, and patches with or without cells were attached to the hearts. After one week, the animals underwent echocardiography to assess for ejection fraction and left ventricular end-diastolic and end-systolic volumes. Following patch formation, the cocultured cells retained viability of >90% over 14 days in culture. The patch was applied to the myocardial surface of the infarcted area after staying 14 days in culture. Interestingly, the BC membrane without cellular treatment showed higher preservation of cardiac dimensions; however, we did not observe improvement in the left ventricular ejection fraction of this group compared to coculture-treated membranes. Our results demonstrated an important role for BC in supporting cells known to produce cardioprotective soluble factors and may thus provide effective future therapeutic outcomes for patients suffering from ischemic heart disease.

Achilles tendon injuries are extremely common and have a significant impact on the physical and mental health of individuals. Both conservative and surgical treatments have unsatisfactory results. The search for new therapeutic tools, using cell therapies with stem cells (SC) and biological tissues, such as amniotic membranes (AM), has proved useful for the regeneration of injured tendons. Background/Objectives: This research was carried out to assess the capacity of tissue repair in animal models of Achilles tendinopathy, in which rats were submitted to complete sections of the tendon, and the effects of using bone marrow SC and/or AM graft are evaluated. Methods: Thirty-seven Wistar rats, submitted to complete surgical section of the Achilles tendon and subsequent tenorrhaphy, were randomized into four groups: Control Group (CG), received saline solution; SC Group (SCG) received an injection of SC infiltrated directly into the tendon; AM Group (AMG), the tendon was covered with an AM graft; SC + AM Group (SC+AMG), has been treated with an AM graft and SC local injection. Six weeks later, the Achilles tendons were evaluated using a histological score and immunohistochemical pro-healing markers such as Interferon-γ, AKT, and mTOR. Results: There were no differences between morphometric histological when evaluating the Achilles tendons of the samples. No significant differences were found regarding the expression of AKT-2 and mTOR markers between the study groups. The main finding was the presence of a higher concentration of Interferon-γ in the group treated with SC and AM. Conclusions: The isolated use of SC, AM, or the combination of SC-AM did not produce significant changes in tendon healing when the histological score was evaluated. Similarly, no difference was observed in the expression of AKT-2 and mTOR markers. An increase in the expression of Interferon-γ was observed in SC+AMG. This suggests that such therapies may be potentially beneficial for the regeneration of injured tendons. However, as tendon repair mechanisms are very complex, further studies should be carried out to verify the benefits of the tendon structure and function.

To investigate the effect of transplantation of stem cells from the bone marrow mononuclear cells (BMMC) associated with 15d-PGJ2-loaded nanoparticles in a rat model of chronic MI. Chronic myocardial infarction (MI) was induced by the ligation of the left anterior descending artery in 40 male Wistar rats. After surgery, we transplanted bone marrow associated with 15d-PGJ2-loaded nanoparticle by intramyocardial injection (106 cells/per injection) seven days post-MI. Myocardial infarction was confirmed by echocardiography, and histological analyses of infarct morphology, gap junctions, and angiogenesis were obtained. Our results from immunohistochemical analyses demonstrated the presence of angiogenesis identified in the transplanted region and that there was significant expression of connexin-43 gap junctions, showing a more effective electrical and mechanical integration of the host myocardium. This study suggests that the application of nanoparticle technology in the prevention and treatment of MI is an emerging field and can be a strategy for cardiac repair.

Disorders of the Achilles tendon are common and have a major socio-economic impact. Current treatments (drugs, physiotherapy, and surgery) do not provide lasting relief, leading to chronicity and recurrence. In this context, experimental studies on regenerative therapies, such as stem cells, and natural and synthetic membranes, have shown promising results in the treatment of tendon lesions. : The present study analyzes the response of tissue to a combination of bone marrow mononuclear cells (BMMCs) and human decellularized amniotic membrane (AM) for the treatment of Achilles tendon lesions in rats. : Forty male Wistar rats were randomized into four treatment groups: SC (stem cells), AM (amniotic membrane), SC + AM (stem cells + amniotic membrane), and C (control). All underwent Achilles tendon sectioning and tenorrhaphy. In the AM and SC + AM groups, the amniotic membrane was sutured over the lesion after the tendon was sutured; in the SC and SC + AM groups, 2 mL of autologous blood from the iliac crest containing BMMCs was applied around the lesion. Animals in Group C received only 2 mL of 0.9% saline around the lesion. After four weeks, the animals were euthanized, and the tendons were sent for histological analysis ( ) and immunohistochemistry (IL-6, IL-4, and IL-13). : Analysis of type I and type III collagen fibers showed no differences between groups. However, the SC + AM group showed the highest expressions of IL-4 and IL-13. : IL-4 and IL-13 are cytokines known to be associated with tissue repair and organization. This suggests that the therapy associated with SC and AM is potentially beneficial in the treatment of injured Achilles tendons. However, further studies are necessary to clarify the benefits of this treatment for the function and biomechanical properties of the tendon and prove whether this association could represent a combined Advanced Therapy Medicinal Product (cATMP). Such a product would contain SC and a biological membrane, providing a mechanical structure for the injured tendon and active biological cells. Another possible medical approach could be immunobiological drugs targeting IL-4 and IL-13.

Background: Tracheal lesions are pathologies derived from the most diverse insults that can result in a fatal outcome. Despite the number of techniques designed for the treatment, a limiting factor is the extent of the extraction. Therefore, strategies with biomaterials can restructure tissues and maintain the organ’s functionality, like decellularized Wharton’s jelly (WJ) as a scaffold. The aim is to analyze the capacity of tracheal tissue regeneration after the implantation of decellularized WJ in rabbits submitted to a tracheal defect. Methods: An in vivo experimental study was undertaken using twenty rabbits separated into two groups (n = 10). Group 1 submitted to a tracheal defect, group 2 tracheal defect, and implantation of decellularized WJ. The analyses were performed 30 days after surgery through immunohistochemistry. Results: Inner tracheal area diameter (p = 0.643) didn’t show significance. Collagen type I, III, and Aggrecan highlighted no significant difference between the groups (both collagens with p = 0.445 and the Aggrecan p = 0.4). Conclusion: The scaffold appears to fit as a heterologous implant and did not trigger reactions such as rejection or extrusion of the material into the recipient. However, these results suggested that although the WJ matrix presents several characteristics as a biomaterial for tissue regeneration, it did not display histopathological benefits in trachea tissue regeneration.

This study assessed the impact of implanting mononuclear stem cells and Wharton’s Jelly (WJ), either separately or together, on left ventricular dysfunction following myocardial infarction in Wistar rats. Functional and histopathological parameters were analyzed, and a rat model of left anterior descending coronary artery ligation was used. Treatments included an intramyocardial injection of 0.9% sodium chloride (control, n = 14), decellularized WJ (n = 12), bone marrow-derived mononuclear cells (BMMC) (n = 12), and bone marrow-derived mononuclear cells (BMMC) combined with WJ (n = 15). Echocardiography assessed the left ventricular function and ejection fraction over four weeks. Histological and immunohistochemical analyses with anti-factor VIII evaluated angiogenesis and collagen types I and III. The results showed no statistically significant effect on ventricular remodeling 30 days post-acute myocardial infarction (AMI). Moreover, the infarct area was significantly smaller in the BMMC + WJ group compared to the control group, suggesting a potential benefit in reducing myocardial scarring. BMMC + WJ therapy demonstrated potential for functional improvement and infarct size reduction 30 days post-infarction. Further studies are needed to confirm its therapeutic benefits.

Myocardial infarction (MI) remains the leading cause of cardiovascular death worldwide and a major cause of heart failure. Recent studies have suggested that cell-based therapies with bone marrow stem cells (BMSC) and human amniotic membrane (hAM) would recover the ventricular function after MI; however, the mechanisms underlying these effects are still controversial. Herein, we aimed to compare the effects of BMSC and hAM in a rat model of heart failure. MI was induced through coronary occlusion, and animals with an ejection fraction (EF) < 50% were included and randomized into three groups: control, BMSC, and hAM. The BMSC and hAM groups were implanted on the anterior ventricular wall seven days after MI, and a new echocardiographic analysis was performed on the 30th day, followed by euthanasia. The echocardiographic results after 30 days showed significant improvements on EF and left-ventricular end-sistolic and end-diastolic volumes in both BMSC and hAM groups, without significant benefits in the control group. New blood vessels, desmine-positive cells and connexin-43 expression were also elevated in both BMSC and hAM groups. These results suggest a recovery of global cardiac function with the therapeutic use of both BMSC and hAM, associated with angiogenesis and cardiomyocyte regeneration after 30 days.

Wound healing is a complex process of repair that involves the interaction between different cell types and involves coordinated interactions between intracellular and extracellular signaling. Bone Marrow Mesenchymal Stem Cells (BMSCs) based and acellular amniotic membrane (AM) therapeutic strategies with the potential for treatment and regeneration of tissue. We aimed to evaluate the involvement of paracrine effects in tissue repair after the flap skin lesion rat model. In the full-thickness flap skin experiment of forty Wistar rats: A total of 40 male Wistar rats were randomized into four groups: group I: control (C; n = 10), with full-thickness lesions on the back, without (BMSCs) or AM (n = 10); group II: injected (BMSCs; n = 10); group III: covered by AM; group IV–injected (AM + BMSCs; n = 10). Cytokine levels, IL-1, and IL-10 assay kits, superoxide dismutase (SOD), glutathione reductase (GRs) and carbonyl activity levels were measured by ELISA 28th day, and TGF-β was evaluated by immunohistochemical, the expression collagen expression was evaluated by Picrosirius staining. Our results showed that the IL-1 interleukin was higher in the control group, and the IL-10 presented a higher mean when compared to the control group. The groups with BMSCs and AM showed the lowest expression levels of TGF-β. SOD, GRs, and carbonyl activity analysis showed a predominance in groups that received treatment from 80%. The collagen fiber type I was predominant in all groups; however, the AM + BMSCs group obtained a higher average when compared to the control group. Our findings suggest that the AM+ BMSCs promote skin wound healing, probably owing to their paracrine effect attributed to the promotion of new collagen for tissue repair.

Objective. Achilles tendon pathologies occur frequently and have a significant socioeconomic impact. Currently, there is no evidence on the best treatment for these pathologies. Cell therapy has been studied in several animal models, and encouraging results have been observed with respect to tissue regeneration. This study is aimed at evaluating the functional and histological effects of bone marrow stem cell or platelet-rich plasma implantation compared to eccentric training in the treatment of Achilles tendinopathy in rats. Methods. Fourty-one male Wistar rats received collagenase injections into their bilateral Achilles tendons (collagenase-induced tendinopathy model). The rats were randomly divided into four groups: stem cells (SC), platelet-rich plasma (PRP), stem cells+platelet-rich plasma (SC+PRP), and control (eccentric training (ET)). After 4 weeks, the Achilles tendons were excised and subjected to biomechanical and histological analyses (Sirius red and hematoxylin-eosin staining). Results. Biomechanical assessments revealed no differences among the groups in ultimate tensile strength or yield strength of the tendons (p=0.157), but there were significant differences in the elastic modulus (MPa; p=0.044) and maximum tensile deformation (p=0.005). The PRP group showed the greatest maximum deformation, and the SC group showed the highest Young’s modulus (elasticity) measurement. In histological analysis (hematoxylin-eosin and Sirius red staining), there were no differences among the groups. Conclusion. PRP and SC+PRP yielded better biomechanical results than eccentric training, showing that these treatments offer better tend function outcomes. This theoretical rationale for the belief that cell therapies can serve as viable alternatives to current treatments chronic fibrotic opens the door for opportunities to continue this research.