Quercetin potentiates transdifferentiation of bone marrow mesenchymal stem cells into the beta cells in vitro

Effects of silibinin on apoptosis and insulin secretion in rat RINm5F pancreatic β-cells

We investigated whether silibinin, a flavonoid, might be useful for treating diabetes mellitus by treating five groups of rat RINm5F β-insulinemia cells as follows: control streptozotocin (STZ) group administered citrate buffer and dimethyl sulfoxide; STZ group administered 20 mM STZ; silibinin group administered 50 µM silibinin; pre-silibinin group administered 50 µM silibinin 5 h before administering 20 mM STZ; simultaneous group administered 50 µM silibinin at the same time as 20 mM STZ. For all groups, MTT assay and flow cytometry were used to evaluate cell viability and necrosis, respectively. Glucose-stimulated insulin secretion (GSIS) and insulin cell content were determined using enzyme-linked immunosorbent assay. Also, expression of genes, pancreatic and duodenal homeobox 1 (pdx1), neuronal differentiation 1 (neurod1), v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog A (mafa), glucose transporter 2 (glut2)) was determined using the real-time polymerase chain reaction. We found that silibinin improved the viability of RINm5F cells and increased GSIS and cellular insulin under glucotoxic conditions. Silibinin increased the expression of neurod1, mafa and glut2, but reduced pdx1 expression. Our findings suggest that silibinin might increase glucose sensitivity and insulin synthesis under glucotoxic conditions, which could be useful for diabetes treatment.

Opportunities and challenges of polyphenols and polysaccharides for type 1 diabetes intervention

Type 1 diabetes (T1D) is an autoimmune disorder characterized by the destruction of insulin-producing pancreatic β cell. It contributes to high mortality, frequent diabetic complications, poor quality of life in patients and also puts a significant economic burden on health care systems. Therefore, the development of new therapeutic strategies is urgently needed. Recently, certain dietary compounds with potential applications in food industry, particularly polyphenols and polysaccharides, have gained increasing attention with their prominent anti-diabetic effects on T1D by modulating β cell function, the gut microbiota and/or the immune system. In this review, we critically discuss the recent findings of several dietary polyphenols and polysaccharides with the potential to protect against T1D and the underlying anti-diabetic mechanisms. More importantly, we highlight the current trends, major issues, and future directions of industrial production of polyphenols- and polysaccharides-based functional foods for preventing or delaying T1D.

Trans-differentiation of mouse mesenchymal stem cells into pancreatic β-like cells by a traditional anti-diabetic medicinal herb Medicago sativa L

Background and aim

Medicago sativa L. is a medicinal herb first cultivated in ancient Iran. Traditionally, it has been utilized for the treatment of several disorders. The plant has been in the human diet for at least 1500 years. Although the hypoglycaemic and anti-diabetic effects of the plant have been approved in traditional medicine, further investigations are needed to support the rational use of M. sativa by humans. This project aimed to evaluate the trans-differentiation potential of bone marrow mesenchymal stem cells (MSCs) to pancreatic β-like cells (insulin-producing cells; IPCs) under the influence of M. sativa extract.

Experimental procedure

Bone marrow MSCs isolated, characterized, and then treated by flower or leaf extract of M. sativa. Beta-cell characteristics of the differentiated cells were evaluated by several techniques, including specific staining, QPCR, immunofluorescence, and ELISA.

Results

The results showed that the differentiated cells were able to express some specific pancreatic genes (PDX-1, insulin1, and insulin2) and proteins (insulin receptor beta, insulin, proinsulin, and C peptide). Furthermore, ELISA analysis indicated the ability of these cells in the production and secretion of insulin, after exposure to glucose.

Conclusion

Overall, both the flower and leaf extract of M. sativa had the potential of differentiation induction of MSCs into IPCs with the characteristics of pancreatic β–like cells. Therefore, M. sativa, as an herbal drug, may be beneficial for the treatment of diseases including diabetes.

PKD1 alleviates oxidative stress-inhibited osteogenesis of rat bone marrow-derived mesenchymal stem cells through TAZ activation

Oxidative stress is known to inhibit osteogenesis and PKD1 is implicated in bone remodeling and skeletogenesis. In the present study, we explored the role of PKD1 in osteogenesis under oxidative stress. H2 O2 was used to induce oxidative stress in rat bone marrow (BM)-mesenchymal stem cells (MSCs) during osteoblast differentiation. Alkaline phosphatase (ALP) activity, calcium deposits, and the RUNX2 marker were assayed to determine osteogenic differentiation. The correlation of PKD1, Sirt1, c-MYC, and TAZ was further confirmed by chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assay. We found that H2 O2 induced the downregulation of PKD1 expression and the upregulation of c-MYC, and Sirt1 was accompanied by decreasing cell viability in BM-MSCs. During osteogenic differentiation, the expression of PKD1 was upregulated significantly whereas Sirt1 tended to be upregulated mildly under normal conditions. Both PKD1 and Sirt1 were upregulated upon oxidative stress. The positive correlation of PKD1 expression with osteogenic differentiation under normal conditions might be hindered by oxidative stress and PKD1 could interact with TAZ under oxidative stress to regulate osteogenic differentiation. Our results suggest that PKD1 may alleviate oxidative stress-inhibited osteogenesis of rat BM-MSCs through TAZ activation.

Viability of Quercetin-Induced Dental Pulp Stem Cells in Forming Living Cellular Constructs for Soft Tissue Augmentation

Autogenous gingival grafts used for root coverage or gingival augmentation procedures often result in donor site morbidity. Living cellular constructs as an exogenous alternative have been proven to be associated with lower morbidity. With the available background information, the present study aims to assess if quercetin-induced living cell constructs, derived from dental pulp stem cells, have the potential to be applied as a tool for soft tissue augmentation. The characterized dental pulp stem cells (positive for CD73, CD90, and negative for CD34, HLA-DR) were expanded in Dulbecco's Modified Eagle's medium (DMEM) supplemented with 10 mM quercetin. The handling properties of the quercetin-induced dental pulp stem cell constructs were assessed by visual, and tactile sensation. A microscopic characterization using hematoxylin and eosin staining, and qRT-PCR-based analysis for stemness-associated genes (OCT4, NANOG, SOX2, and cMyc) was also performed. Dental pulp stem cells without quercetin administration were used as the control. Dental pulp stem cell constructs induced by quercetin easily detached from the surface of the plate, whereas there was no formation in the control cells. It was also simple to transfer the induced cellular construct on the flattened surface. Microscopic characterization of the constructs showed cells embedded in a tissue matrix. Quercetin also increased the expression of stemness-related genes. The use of quercetin-induced DPSC living constructs for soft tissue augmentation could provide an alternative to autogenous soft tissue grafts to lower patient morbidity and improve esthetic outcomes.

Quercetin and vitamin E alleviate ovariectomy-induced osteoporosis by modulating autophagy and apoptosis in rat bone cells

Osteoporosis is the most prevalent metabolic bone disease and one of the most important postmenopausal consequences. The aim of this study was to investigate the effects of quercetin (Q) and vitamin E (vitE) on ovariectomy-induced osteoporosis. Animals were ovariectomized and treated with Q (15 mg/kg/day), vitE (60 mg/kg/day), estradiol (10 µg/kg/day), and Q (7.5 mg/kg/day) + vitE (30 mg/kg/day) for 10 weeks by gavage, and osteoporosis markers and messenger RNA (mRNA) expression of autophagy and apoptosis-related genes were analyzed in serum and tibia of rats. Data indicated that ovariectomy resulted in development of osteoporosis as demonstrated by reduction in serum calcium, bone weight, bone volume, trabeculae volume, and the total number of osteocytes and osteoblasts, and increase in the total number of osteoclasts and serum osteocalcin. Total mRNA expressions of LC3, beclin1, and caspase 3 were also increased and bcl2 expression was decreased in the tibia. By reversing these changes, treatment with Q and vitE markedly improved osteoporosis. In conclusion, Q, and to a lesser extent, vitE, prevented osteoporosis by regulating the total number of bone cells, maybe through regulating autophagy and apoptosis.

Chemoprevention of Prostate Cancer Cells by Vitamin C plus Quercetin: role of Nrf2 in Inducing Oxidative Stress

To assess the effect of sequential treatment with Vitamin C (VC) and Quercetin (Q) on Nrf2-related oxidative stress in PC3 and DU145 cells, viability was measured by MTT assay. Intracellular ROS levels were determined, using 2'-7'-dichlorodihydrofluorescein diacetate fluorescent as a probe. Nrf2 gene expression was investigated by quantitative reverse transcription polymerase chain reaction, and Nrf2 protein levels were defined by western blot analysis. The activity of glutathione peroxidase (GPx), glutathione reductase (GR), nicotinamide adenine dinucleotide phosphate dehydrogenase quinone 1 (NQO1) and hemeoxygenase 1 (HO-1) enzymes were measured. The IC₅₀ values for VC + Q were 263.03-372.1 µM and 144.2-194.1 µM respectively and 200 µM VC + 50 µM Q (dose no.1) and 100 µM VC + 75 µM Q (dose no.2) were selected. Sequential treatment of PC3 cells led to a significant reduction of Nrf2 mRNA expression and protein levels in addition to a significant reduction of GPx, GR and NQO1 enzymatic activity. Although the data was slightly different for DU145 cells after the treatments, in terms of Nrf2 gene expression, we obtained the same results. Our study revealed the significant effects of sequential treatment with VC + Q on Nrf2 suppression in prostate cancer cells.

Primary and Secondary Markers of Doxorubicin-Induced Female Infertility and the Alleviative Properties of Quercetin and Vitamin E in a Rat Model

The incidence of cancer has recently risen among the women at the reproductive age. Therefore, exposure to doxorubicin (DOX) chemotherapy has become a cause of reproductive toxicity followed by secondary destructive effects. The present study aimed to evaluate the effects of quercetin (QCT) and vitamin.E (Vit.E) on doxorubicin-induced toxicity in the ovary and uterus, and the secondary bone-related effects in a rat model. Animals were divided into six groups including control normal saline/corn oil (CON), QCT at 20 mg/Kg, Vit.E at 200 mg/Kg, DOX at accumulative 15 mg/Kg, DOX/QCT, and DOX/Vit.E. After 21 days of treatment, the alterations were analyzed in histoarchitecture, apoptosis, hormones secretion, the gene expression of aromatase and estrogen α-receptor (ER-α) in the uterine and ovarian tissues, and serum levels of bone-related factors. The results demonstrated the ameliorative effects of QCT and Vit.E on doxorubicin caused altered ovarian histology, increased apoptosis, decreased ovarian aromatase and ER-α gene expression (p-value<0.05), decreased estrogen and progesterone levels, decreased ALP (p-value<0.001), and increased osteocalcin (p-value<0.05). The findings suggested that the studied antioxidants administration could be a promising fertility preservation strategy in DOX-treated females.

Stereological and histopathological evaluation of doxorubicin-induced toxicity in female rats' ovary and uterus and palliative effects of quercetin and vitamin E

Doxorubicin (DOX) is a widely used chemotherapeutic agent with demonstrated reproductive toxicity. This study sought to determine the DOX-induced toxicity in the ovary and uterus and the preventive effects of quercetin (QCT) and vitamin E (Vit.E). Female rats were divided into six groups as follows: control, QCT (20 mg/kg), Vit.E (200 mg/kg), DOX (accumulative 15 mg/kg), DOX/QCT, and DOX/Vit.E. After 3 weeks, the toxicity of DOX in ovarian and uterine tissues and the potential palliative effects of QCT and Vit.E were evaluated by histopathological-stereological methods. The findings indicate a dramatic decline in the number of ovarian follicles (p < 0.001), ovarian and its associated structures volume, the volume of the uterus, its layers, and related structures (p < 0.05). Coadministration of QCT and Vit.E with DOX-treated rats demonstrated an alleviative effect on most of the studied parameters. Nevertheless, few adverse effects were recognized concerning these antioxidants administration (p < 0.05). In conclusion, the findings of this study support the protective role of these dietary supplements in the prevention of DOX-induced toxicity in uterine and ovarian tissues.

Amelioration by quercetin of insulin resistance and uterine GLUT4 and ERα gene expression in rats with polycystic ovary syndrome (PCOS)

Insulin resistance (IR) and infertility are two major complications of polycystic ovary syndrome (PCOS), which are the results of changes in certain parts of the reproductive and metabolic systems. We aimed to observe the effect of quercetin on dehydroepiandrosterone (DHEA)-induced PCOS and insulin resistance in rats. All animals were divided into five groups and DHEA was used to induce PCOS. Bodyweight and ovarian morphology of all groups were observed. Fasting blood glucose and insulin levels were analysed. The homeostasis model assessment of insulin resistance (HOMA-IR) method was used for IR level determination. The expression of oestrogen receptor α (ERα) and glucose transporter 4 (GLUT4) genes in the uterus was examined by real-time polymerase chain reaction. Liver hexokinase (HK) and glucokinase (GK) activity was determined using spectrophotometry. Quercetin significantly improved the IR state in PCOS rats. PCOS resulted in a decrease in liver GK and an increase in liver HK specific activity, whereas quercetin increased both liver HK and GK activity. Our data also showed a significant reduction in uterine ERα and GLUT4 expression in the PCOS group, which was increased by quercetin. A remarkable effect of quercetin was the intensive reduction of PCOS-IR and significant induction of uterine GLUT4 and ERα gene expression; it could thus be a possible effective treatment for PCOS and its complications, IR and infertility.

Autologous cord blood in children with cerebral palsy: a review

The aim of this narrative review is to report on the current knowledge regarding the clinical use of umbilical cord blood (CB) based on articles from PubMed and clinical trials registered on ClinicalTrials.gov. An increasing amount of evidence suggests that CB may be used for both early diagnostics and treatment of cerebral palsy. The acidity of CB and its biochemical parameters, including dozens of cytokines, growth factors, and other metabolites (such as amino acids, acylcarnitines, phosphatidylcholines, succinate, glycerol, 3-hydroxybutyrate, and O-phosphocholine) are predictors of future neurodevelopment. In addition, several clinical studies confirmed the safety and efficacy of CB administration in both autologous and allogeneic models, including a meta-analysis of five clinical trials involving a total of 328 participants. Currently, nine clinical trials assessing the use of autologous umbilical CB in children diagnosed with hypoxic-ischemic encephalopathy or cerebral palsy are in progress. The total population assessed in these trials exceeds 2500 patients.

The use of mesenchymal stem cells for the treatment of progressive retinal diseases: a review

Some ocular diseases, such as dystrophies, retinal and macular degeneration, optic nerve atrophy, and Stargardt disease, are progressive and irreversible. In this review, we focus on the use of mesenchymal stem cells (MSCs) in the treatment of these diseases. In animal studies, MSC transplantation significantly delayed retinal degeneration, led to the regeneration of cone cells, and supported the survival of retinal ganglion cells and axon regeneration. In clinical practice, patients with Behcet's disease with retinal vasculitis who received MSC injections experienced a decrease in retinal vasculitis but no improvement in vision acuity. Nonetheless, there is no evidence that MSCs are carcinogenic, and they even reduce the size of tumors in vitro. Furthermore, MSCs do not trigger the immune response.

Potential Non-neoplastic Applications for Polyphenols in Stem Cell Utilization

While polyphenols may have important effects on pluripotential stem cells that make them noteworthy as potential antineoplastic agents, their action on stem cells may portend other health benefits, such as treatments for cardiovascular and neurocognitive disorders. Resveratrol, the beststudied polyphenol, has been found to enable stem cells to differentiate into cardiomyocytes, neurons, osteocytes, and pancreatic beta cells, as well as facilitating augmentation of stem cell populations and protecting them from toxic injury. Curcumin protects mesenchymal stem cells from toxicity, and prevents them from facilitating chondrocytic hypertrophy. Quercetin enabled osteocytic and pancreatic beta cell differentiation, and protected neuronal stem cells from injury. Epigallocatechin gallate prevented damage to osteocyte precursors and averted differentiation into undesirable adipocytes. Genistein facilitated osteogenesis while preventing adipogenesis. Several other polyphenols, daidzein, caffeic and chlorogenic acid, kaempferol, and piceatannol, protect stems cells from reactive oxygen species and foster stem cells differentiation away from adipocytic and toward osteocytic lineages. Further research should better elucidate the pharmacokinetic profiles of each polyphenol, explore novel delivery systems, and expand investigation beyond rodent models to additional species.

Deiodinases and stem cells: an intimate relationship

Thyroid hormone is a major determinant of tissue functions in vivo. The deiodinase family controls the tissue-specific activation or inactivation of intracellular thyroid hormones. Precise control of the T3-dependent transcriptional program is required by multiple cell systems, including the stem cell. In this context, the identification of a close connection between thyroid hormones and different signal pathways involved in the control of stem cell functions suggested that the deiodinases may play a role in the definition of stem cell biology and physiology. Stem cells have an unlimited self-renewal capacity and the potential to differentiate into different types of mature cells. Deciphering how all these events are achieved, how the T3 signal is controlled and integrated in stem cells and their niches, and how it can impact on them is essentially unknown and represents a challenge for coming years. In this review, I will explore the role played by the deiodinases in the modulation of the TH signal in stem cells of adult tissues, namely muscle and intestine, and how their actions control the delicate balance among self-renewal, proliferation and differentiation. Elucidation of the molecular mechanisms presiding thyroid hormone action in stem cells may reveal therapeutic potential, for example in the fields of regenerative diseases and cancer.

Pleckstrin homology-like domain family A, member 3 (PHLDA3) deficiency improves islets engraftment through the suppression of hypoxic damage

Islet transplantation is a useful cell replacement therapy that can restore the glycometabolic function of severe diabetic patients. It is known that many transplanted islets failed to engraft, and thus, new approaches for overcoming graft loss that may improve the outcome of future clinical islet transplantations are necessary. Pleckstrin homology-like domain family A, member 3 (PHLDA3) is a known suppressor of neuroendocrine tumorigenicity, yet deficiency of this gene increases islet proliferation, prevents islet apoptosis, and improves their insulin-releasing function without causing tumors. In this study, we examined the potential use of PHLDA3-deficient islets in transplantation. We observed that: 1) transplanting PHLDA3-deficient islets into diabetic mice significantly improved their glycometabolic condition, 2) the improved engraftment of PHLDA3-deficient islets resulted from increased cell survival during early transplantation, and 3) Akt activity was elevated in PHLDA3-deficient islets, especially under hypoxic conditions. Thus, we determined that PHLDA3-deficient islets are more resistant against stresses induced by islet isolation and transplantation. We conclude that use of islets with suppressed PHLDA3 expression could be a novel and promising treatment for improving engraftment and consequent glycemic control in islet transplantation.

Immunotherapy for type 1 diabetes

INTRODUCTION

Although many approaches have been tested to overcome the insulin dependence caused by the pancreatic β-cells destruction observed in individuals affected by type 1 diabetes (T1D), medical research has largely failed to halt the onset or to reverse T1D.

METHODS

In this work, the state of the art of immunotherapy will be examined, and the most important achievement in the field will be critically discussed. Particularly, we will focus on the clinical aspect, thus avoiding the tedious preclinical work done in NOD mice, which has been so poorly translated to the bedside.

CONCLUSIONS

Stem cell therapies achieved thus this far the most promising results, while immune ablation and standard immunosuppressants did not maintain the premises of preclinical results. The next step will be to generate a feasible and safe clinical approach in order to cure the thousands of patients affected by T1D.

Protective effects of quercetin on nicotine induced oxidative stress in 'HepG2 cells'

Nicotine is a natural component of tobacco plants and is responsible for the addictive properties of tobacco. Nicotine has been recognized to result in oxidative stress by inducing the generation of reactive oxygen species (ROS). The purpose of this work was to estimate the hepatotoxicity effect of nicotine on viability and on antioxidant defense system in cultures of HepG2 cell line and the other hand, ameliorative effect of quercetin (Q) as an antioxidant was analyzed. Nicotine induced concentration dependent loss in HepG2 cell line viability. The results indicated that nicotine decreased activity of superoxide dismutase (SOD) and glutathione reductase (GR) and increased activities of catalase (CAT) and glutathione peroxidase (GPx) and glutathione (GSH) content in the HepG2 cells. Q significantly increased activity of SOD, GR and GSH content and decreased activity of GPX in nicotine + Q groups. Our data demonstrate that Q plays a protective role against the imbalance elicited by nicotine between the production of free radicals and antioxidant defense systems, and suggest that administration of this antioxidant may find clinical application where cellular damage is a consequence of ROS.