Extracellular vesicles secreted by bone marrow stem cells mediate angiogenesis for the treatment of diabetic ulcers: A systematic review and meta-analysis of preclinical studies

Background

Diabetic ulcers (DUs) typically occur in patients with vascular diseases and diabetes. Extracellular vesicles secreted by bone marrow-derived stem cells (BMSC-EVs) represent a cell-free therapy that has emerged as a promising alternative for treating DU, especially due to significant advancements in the understanding of their role in promoting angiogenesis; however, their application in DU treatment remains in the preclinical stage, and their effectiveness is still uncertain. Therefore, we conducted this meta-analysis to evaluate the therapeutic efficacy of BMSC-EVs in treating DU and to expedite the clinical translation of BMSC-EV therapy for DU.

Methods

We conducted a comprehensive search of PubMed, Cochrane Library, MEDLINE, EMBASE, China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP Database, and our self-constructed database of Chinese Biomedical Literature up to May 2023 to identify preclinical studies related to the therapeutic use of extracellular vesicles secreted by bone marrow-derived stem cells for treating diabetic ulcers. Outcome measures included wound healing rate, neovascularization density, a-sma, and CD31. RevMan 5 software was employed for all statistical analyses.

Results

In this meta-analysis, a total of 11 studies involving 103 animals were identified. The pooled analysis indicated that BMSC-EV treatment showed a superior wound healing rate compared to that of the control group (SMD = 1.06, 95% CI [0.52, 1.60], P = 0.0001). In the subgroup analysis, EV combined with new materials or drug therapy performed better than the sole injection of extracellular vesicles (SMD = 1.85, 95% CI [0.87, 2.82], P < 0.00001). BMSC-EV treatment also resulted in a higher number of neovascular structures compared to the control group(SMD = 5.80, 95% CI[0.89,10.71], P = 0.006). In the subgroup analysis, EV combined therapy showed a significant difference in the number of blood vessels compared to the sole injection of extracellular vesicles (SMD = 4.90, 95% CI[2.64,7.15], P < 0.00001). However, BMSCs-EV treatment did not demonstrate any statistically significant difference in the angiogenesis-related indicators CD31 and α-SMA compared to the control group (SMD = 1.61, 95% CI[-0.51,3.74], P = 0.14).

Conclusion

According to the current meta-analysis, BMSC-EV therapy can enhance the healing of diabetic ulcers and promote wound angiogenesis, particularly when used in combination with novel dressings or other drugs, which further accelerates the healing process of diabetic ulcers. To establish the most effective parameters for EV treatment in diabetic ulcers, future research should promptly progress into clinical trials.

IFITM3 overexpression reverses insufficient healing benefits of small extracellular vesicles from high-fat-diet BMSCs in sepsis via the HMGB1 pathway

Bone marrow mesenchymal stem cells (BMSCs) are a promising new therapy for sepsis, a common cause of death in hospitals. However, the global epidemic of metabolic syndromes, including obesity and pre-obesity, threatens the health of the human BMSC pool. The therapeutic effects of BMSCs are primarily due to the secretion of the small extracellular vesicles containing lipids, proteins, and RNA. Accordingly, studies on BMSCs, their small extracellular vesicles, and their modifications in obese individuals are becoming increasingly important. In this study, we investigated the therapeutic potential of small extracellular vesicles (sEVs) from high-fat diet BMSCs (sEVsHFD) in sepsis-induced liver-heart axis injury. We found that sEVsHFD yielded diminished therapeutic benefits compared to sEVs from chow diet BMSCs (sEVsCD). We subsequently verified that IFITM3 significantly differed in sEVsCD and sEVsHFD, alternating in septic liver tissue, and indicating its potential as a remodeling target of sEVs. IFITM3-overexpressed high-fat-diet BMSCs (HFD-BMSCs) showed that corresponding sEVs (sEVsHFD-IFITM3) markedly ameliorated liver-heart axis injury during sepsis. Lastly, we identified the protective action mechanisms of sEVsHFD-IFITM3 in sepsis-induced organ failure and HMGB1 expression and secretion was altered in septic liver and serum while HMGB1 has been demonstrated as a critical mediator of multi-organ failure in sepsis. These findings indicate that IFITM3 overexpression regenerates the therapeutic benefit of sEVs from HFD-BMSCs in sepsis via the HMGB1 pathway.

Using a developed co-culture device to evaluate the proliferation of bone marrow stem cells by stimulation with platelet-rich plasma and electromagnetic field

BACKGROUNDS

Bone marrow stem cell can differentiate to osteoblast by growth factors, pulsed low-intensity ultrasound and electric magnetic field. In the research, bone marrow stem cells were cultured; bone marrow stem cells in culture can be stimulated by platelet-rich plasma and electric field.

METHODS

The culture well of the co-cultivation device has a radius of 7.5 mm and a depth of 7 mm. It is divided into two sub-chambers separated by a 3 mm high and 1 mm wide barrier. The bone marrow stem cells were seeded at a density of 2 × 104 cells and the medium volume was 120μl. Platelet-rich plasma (PRP) or platelet-poor plasma (PPP) was added to the other sub-chamber at a volume of 10μl. The bone marrow stem cells were subjected to different electric fields (0 ~ 1 V/cm) at a frequency of 70 kHz for 60 min.

RESULTS

The highest osteogenic capacity of bone marrow stem cells was achieved by addition of PRP to electric field stimulation (0.25 V/cm) resulted in a proliferation rate of 599.78%. In electric field stimulation (0.75 V/cm) with PPP, the proliferation rate was only 10.46%.

CONCLUSIONS

Bone marrow stem cell with PRP in the co-culture device combined with electric field at 0.25 V/cm strength significantly promoted the growth of bone marrow stem cells.

Alkali-treated titanium dioxide promotes formation of proteoglycan layer and altered calcification and immunotolerance capacity in bone marrow stem cell

Introduction

In this study, we report that a proteoglycans (PGs)-layer between the bone and titanium dioxide (TiO2) surface after osseointegration improved the calcification capacity and immunotolerance of human bone marrow mesenchymal stem cells (hBMSCs) on TiO2. Alkaline treatment of TiO2 is a method for promoting osteogenesis in hBMSCs. We hypothesized that promotion of osteogenesis due to alkaline treatment was caused by changing PGs-layer on TiO2.

Objective

This study aimed to analyze whether alkaline treatment of TiO2 affects PGs-layer formation and immunotolerance in hBMSCs.

Methods

The topology and wettability of the alkaline-treated titanium (Ti-Al) and unprocessed titanium (Ti-MS) surfaces were characterized. Initial cell attachment, cell proliferation, calcification capacity, alkaline phosphatase activity, PGs-layer formation, PGs function, and the expression of osteogenic and immunotolerance-related genes were analyzed. The conditioned medium (CM) from hBMSCs grown on Ti-Al and Ti-MS was added to macrophages (hMps) and Jurkat cells, and immunotolerance gene expression in these cells was analyzed.

Results

hBMSCs cultured on Ti-Al showed increased initial cell attachment, cell proliferation, PG-layer formation, and osteogenic capacity compared with hBMSCs on Ti-MS. Gene expression of indoleamine 2,3-dioxygenase (IDO) in the hBMSCs cultured on Ti-Al was higher than that in the hBMSCs on Ti-MS. CM from hBMSCs did not affect markers of M1 and M2 macrophages in hMps. CM from hBMSCs cultured on Ti-Al altered the gene expression of Foxp3 in Jurkat cells compared to that of CM from hBMSCs on Ti-MS.

Significance

These results suggest that alkaline treatment of TiO2 altered PGs-layer formation, and changed the osteogenesis and immunotolerance of hBMSCs.

Codonopsis pilosula polysaccharides promote osteogenic differentiation and inhibit lipogenic differentiation of rat bone marrow stem cells by activating β-catenin

Aberrant bone marrow mesenchymal stem cell (BMSC) lineage differentiation leads to osteoporosis. Codonopsis pilosula polysaccharides (CPPs) have been widely used in traditional Chinese medicines, due to their multiple pharmacological actions. However, little is known regarding their effects on BMSC differentiation. This study aimed to identify the effects and mechanisms of CPPs on osteogenic and adipogenic differentiation in rat BMSCs. An osteoporosis model was established in Sprague-Dawley (SD) rats through bilateral ovariectomy (OVX), and be applied to observe the effect of CPPs on osteoporosis in vivo. The ability of CPPs to affect rBMSC proliferation was determined using the CCK-8 assay, and the osteogenic differentiation of rBMSCs measured by ALP and Alizarin Red S staining. The adipogenic differentiation of rBMSCs was measured by Oil Red O staining. The mRNA and protein levels related to osteogenesis and adipogenic differentiation of rBMSCs were measured using qRT-PCR and western blotting, respectively. Cellular immunofluorescence was used to detect cytokine expression and localisation in rBMSCs. We observed that CPPs ameliorated bone loss in OVX rats. CPPs considerably enhanced osteogenic differentiation by increasing ALP activity and the prevalence of mineralised nodules and promoting the mRNA and protein expression of osteogenic differentiation markers (RUNX2, COL I, ALP, and OPN). Furthermore, it inhibited the accumulation of lipid vesicles in the cytoplasm and the mRNA and protein expression levels of adipogenic differentiation markers (PPARγ and C/EBPα) in a concentration-dependent manner. Meanwhile, CPPs notably increased the mRNA and protein expression of β-catenin, the core protein of the Wnt/β-catenin signaling pathway, in a concentration-dependent manner. Adding DKK1, a mature inhibitor of the Wnt/β-catenin signaling pathway, partially suppressed CPP-stimulated β-catenin activation, and reversed the acceleration of osteogenic differentiation and the inhibition of lipogenic differentiation. Our observations demonstrated CPPs ameliorate bone loss in OVX rats in vivo, and favour osteogenic differentiation while inhibit adipogenic differentiation of rBMSCs in vitro. The findings suggested that CPPs could serve as functional foods for bone health, and have great potential for the prevention and treatment of osteoporosis.

Proteomic profiling of regenerated urinary bladder tissue with stem cell seeded scaffold composites in a non-human primate bladder augmentation model

Urinary bladder insult can be caused by environmental, genetic, and developmental factors. Depending upon insult severity, the bladder may lose its ability to maintain capacity and intravesical pressures resulting in renal deterioration. Bladder augmentation enterocystoplasty (BAE) is employed to increase bladder capacity to preserve renal function using autologous bowel tissue as a "patch." To avoid the clinical complications associated with this procedure, we have engineered composite grafts comprised of autologous bone marrow mesenchymal stem cells (MSCs) with CD34+ hematopoietic stem/progenitor cells (HSPCs) co-seeded onto a pliable synthetic scaffold [POCO; poly(1,8-octamethylene-citrate-co-octanol)] or a biological scaffold (SIS; small intestinal submucosa) to regenerate bladder tissue in a baboon bladder augmentation model. We set out to determine the protein expression profile of bladder tissue that has undergone regeneration with the aforementioned stem cell seeded scaffolds along with baboons that underwent BAE. Data demonstrate that POCO and SIS grafted animals share high protein homogeneity between native and regenerated tissues while BAE animals displayed heterogenous protein expression between the tissues following long-term engraftment. We posit that stem cell seeded scaffolds can recapitulate tissue that is almost indistinguishable from native tissue at the protein level and may be used in lieu of procedures such as BAE.

Stem cell therapy combined with luteolin alleviates experimental neuropathy

Neuropathic pain is a chronic condition that causes long-term burning sensations. Despite significant efforts, current treatments for neuropathic pain are ineffective in curing the condition, which means new therapeutic options must be developed. One such option is the use of stem cell therapy in combination with anti-inflammatory herbal components, which has shown promise in treating neuropathic pain. The study aimed to investigate the effects of bone marrow mesenchymal stem cells (BM-MSCs) with luteolin on sensory deficits and pathological changes in a neuropathic model. The results showed that luteolin, either alone or in combination with BM-MSCs, effectively reduced sensory deficits related to mechanical and thermal hypersensitivity. In addition, luteolin alone and combined with BM-MSCs reduced oxidative stress in neuropathic rats and inhibited cellular responses, particularly reactive astrocytes. The study concluded that combining luteolin and BM-MSCs may offer an effective therapeutic strategy for patients with neuropathic pain, although further research is needed.

Bone marrow derived mesenchymal stem cells therapy for rheumatoid arthritis - a concise review of past ten years

Rheumatoid arthritis is an autoimmune disorder characterized by swelling in synovial joints and erosion of bones. The disease is normally treated with conventional drugs which provide only temporary relief to the symptoms. Over the past few years, mesenchymal stromal cells have become the center of attention for treating this disease due to their immuno-modulatory and anti-inflammatory characteristics. Various studies on treatment of rheumatoid arthritis by using these cells have shown positive outcomes in terms of reduction in the level of pain as well as improvement of the function and structure of joints. Mesenchymal stromal cells can be derived from multiple sources, however, the ones derived from bone marrow are considered most beneficial for treating several disorders including rheumatoid arthritis on account of being safer and more effective. This review summarizes all the preclinical and clinical studies which were conducted over the last ten years for therapy of rheumatoid arthritis utilizing these cells. The literature was reviewed using the terms "mesenchymal stem/stromal cells and rheumatoid arthritis'' and "bone marrow derived mesenchymal stromal cells and therapy of rheumatoid arthritis''. Data was extracted to enable the readers to have access to the most relevant information regarding advancement in therapeutic potential of these stromal cells. Additionally, this review will also help in fulfilling any gap in current knowledge of readers about the outcome of using these cells in animal models, cell line and in patients suffering from rheumatoid arthritis and other autoimmune disorders as well.

Ovarian rescue in women with premature ovarian insufficiency: facts and fiction

The ovary has a comparatively short functional lifespan compared with other organs, and genetic and pathological injuries can further shorten its functional life. Thus, preserving ovarian function should be considered in the context of women with threats to ovarian reserve, such as ageing, premature ovarian insufficiency (POI) and diminished ovarian reserve (DOR). Indeed, one-third of women with POI retain resting follicles that can be reactivated to produce competent oocytes, as proved by the in-vitro activation of dormant follicles. This paper discusses mechanisms and clinical data relating to new therapeutic strategies using ovarian fragmentation, stem cells or platelet-rich plasma to regain ovarian function in women of older age (>38 years) or with POI or DOR. Follicle reactivation techniques show promising experimental outcomes and have been successful in some cases, when POI is established or DOR diagnosed; however, there is scarce clinical evidence to warrant their widespread clinical use. Beyond these contexts, also discussed is how new insights into the biological mechanisms governing follicular dynamics and oocyte competence may play a role in reversing ovarian damage, as no technique modifies oocyte quality. Additional studies should focus on increasing follicle number and quality. Finally, there is a small but important subgroup of women lacking residual follicles and requiring oocyte generation from stem cells.

Cell therapy in ALS: An update on preclinical and clinical studies

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the loss of motor neurons and neuromuscular impairment leading to complete paralysis, respiratory failure and premature death. The pathogenesis of the disease is multifactorial and noncell-autonomous involving the central and peripheral compartments of the neuromuscular axis and the skeletal muscle. Advanced clinical trials on specific ALS-related pathways have failed to significantly slow the disease. Therapy with stem cells from different sources has provided a promising strategy to protect the motor units exerting their effect through multiple mechanisms including neurotrophic support and excitotoxicity and neuroinflammation modulation, as evidenced from preclinical studies. Several phase I and II clinical trial of ALS patients have been developed showing positive effects in terms of safety and tolerability. However, the modest results on functional improvement in ALS patients suggest that only a coordinated effort between basic and clinical researchers could solve many problems, such as selecting the ideal stem cell source, identifying their mechanism of action and expected clinical outcomes. A promising approach may be stem cells selected or engineered to deliver optimal growth factor support at multiple sites along the neuromuscular pathway. This review covers recent advances in stem cell therapies in animal models of ALS, as well as detailing the human clinical trials that have been done and are currently undergoing development.

Bone Cells Metabolic Changes Induced by Ageing

Bone is a living organ that exhibits active metabolic processes, presenting constant bone formation and resorption. The bone cells that maintain local homeostasis are osteoblasts, osteoclasts, osteocytes and bone marrow stem cells, their progenitor cells. Osteoblasts are the main cells that govern bone formation, osteoclasts are involved in bone resorption, and osteocytes, the most abundant bone cells, also participate in bone remodeling. All these cells have active metabolic activities, are interconnected and influence each other, having both autocrine and paracrine effects. Ageing is associated with multiple and complex bone metabolic changes, some of which are currently incompletely elucidated. Ageing causes important functional changes in bone metabolism, influencing all resident cells, including the mineralization process of the extracellular matrix. With advancing age, a decrease in bone mass, the appearance of specific changes in the local microarchitecture, a reduction in mineralized components and in load-bearing capacity, as well as the appearance of an abnormal response to different humoral molecules have been observed. The present review points out the most important data regarding the formation, activation, functioning, and interconnection of these bone cells, as well as data on the metabolic changes that occur due to ageing.

Greater angiogenic and immunoregulatory potency of bFGF and 5-aza-2'-deoxycytidine pre-treated menstrual blood stem cells in compare to bone marrow stem cells in rat model of myocardial infarction

BACKGROUND

This study is designed to compare the menstrual blood stem cells (MenSCs) and bone marrow stem cells (BMSCs)-secreted factors with or without pre-treatment regimen using basic fibroblast growth factor (bFGF) and 5-aza-2'-deoxycytidine (5-aza) and also regenerative capacity of pre-treated MenSCs and/or BMSCs in a rat model of myocardial infarction (MI).

METHODS

BMSCs and MenSCs were pre-treated with bFGF and 5-aza for 48 h and we compared the paracrine activity by western blotting. Furthermore, MI model was created and the animals were divided into sham, MI, pre-treated BMSCs, and pre-treated MenSCs groups. The stem cells were administrated via tail vain. 35 days post-MI, serum and tissue were harvested for further investigations.

RESULTS

Following pre-treatment, vascular endothelium growth factor, hypoxia-inducible factor-1, stromal cell-derived factor-1, and hepatocyte growth factor were significantly increased in secretome of MenSCs in compared to BMSCs. Moreover, systemic administration of pre-treated MenSCs, leaded to improvement of cardiac function, preservation of myocardium from further subsequent injuries, promotion the angiogenesis, and reduction the level of NF-κB expression in compared to the pre-treated BMSCs. Also, pre-treated MenSCs administration significantly decreased the serum level of Interleukin 1 beta (IL-1β) in compared to the pre-treated BMSCs and MI groups.

CONCLUSIONS

bFGF and 5-aza pre-treated MenSCs offer superior cardioprotection compare to bFGF and 5-aza pre-treated BMSCs following MI.

Site-specific characteristics of bone and progenitor cells in control and ovariectomized rats

One-third of postmenopausal women experience at least one osteoporotic bone fracture in their lifetime that occurs spontaneously or from low-impact events. However, osteoporosis-associated jaw bone fractures are extremely rare. It was also observed that jaw bone marrow stem cells (BMSCs) have a higher capacity to form mineralized tissues than limb BMSCs. At present, the underlying causes and mechanisms of variations between jaw bone and limb bone during postmenopause are largely unknown. Thus, the objective of the current study was to examine the site-specific effects of estrogen deficiency using comprehensive analysis of bone quantity and quality, and its association with characterization of cellular components of bone. Nine rats (female, 6 months old) for each bilateral sham and ovariectomy (OVX) surgery were obtained and maintained for 2 months after surgery. A hemi-mandible and a femur from each rat were characterized for parameters of volume, mineral density, cortical and trabecular morphology, and static and dynamic mechanical analysis. Another set of 5 rats (female, 9 months old) was obtained for assays of BMSCs. Following cytometry to identify BMSCs, bioassays for proliferation, and osteogenic, adipogenic, chondrogenic differentiation, and cell mitochondrial stress tests were performed. In addition, mRNA expression of BMSCs was analyzed. OVX decreased bone quantity and quality (mineral content, morphology, and energy dissipation) of femur while those of mandible were not influenced. Cellular assays demonstrated that mandible BMSCs showed greater differentiation than femur BMSCs. Gene ontology pathway analysis indicated that the mandibular BMSCs showed most significant differential expression of genes in the regulatory pathways of osteoblast differentiation, SMAD signaling, cartilage development, and glucose transmembrane transporter activity. These findings suggested that active mandibular BMSCs maintain bone formation and mineralization by balancing the rapid bone resorption caused by estrogen deficiency. These characteristics likely help reduce the risk of osteoporotic fracture in postmenopausal jawbone.

Myocardial regeneration protocols towards the routine clinical scenario: An unseemly path from bench to bedside

Heart failure secondary to cardiomyocyte loss and/or dysfunction is the number one killer worldwide. The field of myocardial regeneration with its far-reaching primary goal of cardiac remuscularization and its hard-to-accomplish translation from bench to bedside, has been filled with ups and downs, steps forward and steps backward, controversies galore and, unfortunately, scientific scandals. Despite the present morass in which cardiac remuscularization is stuck in, the search for clinically effective regenerative approaches remains keenly active. Starting with a concise overview of the still highly debated regenerative capacity of the adult mammalian heart, we focus on the main interventions, that have reached or are close to clinical use, critically discussing key findings, successes, and failures. Finally, some promising and innovative approaches for myocardial repair/regeneration still at the pre-clinical stage are discussed to offer a holistic view on the future of myocardial repair/regeneration for the prevention/management of heart failure in the clinical scenario.

FUNDING

This research was funded by Grants from the Ministry of University and Research PRIN2015 2015ZTT5KB_004; PRIN2017NKB2N4_005; PON-AIM - 1829805-2.

Bone marrow mesenchymal stromal cells for diabetes therapy: touch, fuse, and fix?

Bone marrow mesenchymal stromal cells (BM-MSCs) have anti-inflammatory and pro-survival properties. Naturally, they do not express human leukocyte antigen class II surface antigens and have immunosuppressive capabilities. Together with their relatively easy accessibility and expansion, they are an attractive tool for organ support in transplantation and regenerative therapy. Autologous BM-MSC transplantation alone or together with transplanted islets improves β-cell function, graft survival, and glycemic control in diabetes. Albeit MSCs’ capacity to transdifferentiate into β-cell is limited, their protective effects are mediated mainly by paracrine mechanisms through BM-MSCs circulating through the body. Direct cell–cell contact and spontaneous fusion of BM-MSCs with injured cells, although at a very low rate, are further mechanisms of their supportive effect and for tissue regeneration. Diabetes is a disease of long-term chronic inflammation and cell therapy requires stable, highly functional cells. Several tools and protocols have been developed by mimicking natural fusion events to induce and accelerate fusion in vitro to promote β-cell-specific gene expression in fused cells. BM-MSC-islet fusion before transplantation may be a strategy for long-term islet survival and improved function. This review discusses the cell-protective and anti-inflammatory characteristics of BM-MSCs to boost highly functional insulin-producing cells in vitro and in vivo, and the efficacy of their fusion with β-cells as a path to promote β-cell regeneration.

Mesh-like electrospun membrane loaded with atorvastatin facilitates cutaneous wound healing by promoting the paracrine function of mesenchymal stem cells

BACKGROUND

Functional electrospun membranes are promising dressings for promoting wound healing. However, their microstructure and drug loading capacity need further improvements. It is the first time to design a novel mesh-like electrospun fiber loaded with atorvastatin (ATV) and investigated its effects on paracrine secretion by bone marrow-derived mesenchymal stem cells (BMSCs) and wound healing in vivo.

METHODS

We fabricated a mesh-like electrospun membrane using a copper mesh receiver. The physical properties of the membranes were evaluated by SEM, FTIR spectroscopy, tensile strength analysis, and contrast angle test. Drug release was measured by plotting concentration as a function of time. We tested the effects of conditioned media (CM) derived from BMSCs on endothelial cell migration and angiogenesis. We used these BMSCs and performed RT-PCR and ELISA to evaluate the expressions of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF) genes and proteins, respectively. The involvement of FAK and AKT mechanotransduction pathways in the regulation of BMSC secretion by material surface topography was also investigated. Furthermore, we established a rat model of wound healing, applied ATV-loaded mesh-like membranes (PCL/MAT) seeded with BMSCs on wounds, and assessed their efficacy for promoting wound healing.

RESULTS

FTIR spectroscopy revealed successful ATV loading in PCL/MAT. Compared with random electrospun fibers (PCL/R) and mesh-like electrospun fibers without drug load (PCL/M), PCL/MAT induced maximum promotion of human umbilical vein endothelial cell (HUVEC) migration. In the PCL/MAT group, the cell sheet scratches were nearly closed after 24 h. However, the cell sheet scratches remained open in other treatments at the same time point. The PCL/MAT promoted angiogenesis and led to the generation of longer tubes than the other treatments. Finally, the PCL/MAT induced maximum gene expression and protein secretion of VEGF and b-FGF. As for material surface topography effect on BMSCs, FAK and AKT signaling pathways were shown to participate in the modulation of MSC morphology and its paracrine function. In vivo, PCL/MAT seeded with BMSCs significantly accelerated healing and improved neovascularization and collagen reconstruction in the wound area compared to the other treatments.

CONCLUSIONS

The mesh-like topography of fibrous scaffolds combined with ATV release creates a unique microenvironment that promotes paracrine secretion of BMSCs, thereby accelerating wound healing. Hence, drug-loaded mesh-like electrospun membranes may be highly efficacious for wound healing and as artificial skin. It is a promising approach to solve the traumatic skin defect and accelerate recovery, which is essential to developing functional materials for future regenerative medicine.

In Vivo Bioluminescent Imaging of Bone Marrow-Derived Mesenchymal Stem Cells in Mice

Mesenchymal stem cells (MSCs) are multipotent adult stem cells present in multiple tissues, such as bone marrow, adipose tissue, umbilical cord, and amniotic fluid. MSCs can differentiate into multilineage cells under defined conditions in vitro and in vivo. MSCs have been shown to have therapeutic effects on various types of diseases. Noninvasive in vivo monitoring of MSCs is considered one of the important techniques for developing cell therapy. In this protocol, we introduce strategized MSCs derived from bone marrow (BM-MSCs) of knock-in mouse model expressing mCherry-Renilla luciferase (mCherry-RLuc) for noninvasive bioluminescence imaging (BLI) of injected BM-MSCs in vivo.

Impaired bone marrow microenvironment and stem cells in transfusion-dependent beta-thalassemia

Beta-thalassemia (BT) is a hereditary disease caused by abnormal hemoglobin synthesis with consequent ineffective erythropoiesis. Patients with thalassemia major are dependent on long-term blood transfusions with associated long-term complications such as iron overload (IO). This excess iron can result in tissue damage, impaired organ function, and increased morbidity. Growing evidence has demonstrated that IO contributes to impairment of the bone marrow (BM) microenvironment that largely impacts the function of BM mesenchymal stem cells, hematopoietic stem cells, and endothelial cells. In this article, we review recent progress in the understanding of iron metabolism and the perniciousness induced by IO. We highlight the importance of understanding the cross-talk between BM stem cells and the BM microenvironment, particularly the pathological effect of IO on BM stem cells and BT-associated complications. We also provide an update on recent novel therapies to cure transfusion-dependent beta-thalassemia and iron overload-induced complications for their future clinical application.

Investigation into the effects of leukemia inhibitory factor on the bone repair capacity of BMSCs-loaded BCP scaffolds in the mouse calvarial bone defect model

Leukemia inhibitory factor (LIF) is known to play a major role in bone physiology. In the present study, we examined the in vitro effects of LIF on osteoblast differentiation of bone marrow stem cells (BMSCs) and explored in vivo effects of LIF on the bone repair capacity of BMSCs-loaded biphasic calcium phosphate (BCP) scaffolds in mouse calvarial bone defect model. The mRNA and protein expression levels in the BMSCs were determined by quantitative real-time PCR and western blot, respectively; the in vitro osteoblast differentiation of the BMSCs was evaluated by using Alizarin Red S staining. The bone volume and bone density in the repaired calvarial bone defect were determined by Micro-CT. Bone regeneration was also histologically evaluated by hematoxylin and eosin staining and Masson's trichrome staining. Hypoxia treatment induced the up-regulation of Lif mRNA and LIF protein in the BMSCs. Lif overexpression up-regulated the mRNA expression levels of osteopontin and Runt-related transcription factor 2, and increased intensity of Alizarin Red S staining in the BMSCs; while Lif silence exerted the opposite effects. The in vivo studies showed that implantation of Lif-overexpressing BMSCs-loaded BCP scaffolds significantly increased the bone volume and bone density at 4 and 8 weeks after transplantation, and promoted the regeneration of bone tissues in the mouse calvarial bone defect at 8 weeks after transplantation when compared to the BMSCs-loaded BCP scaffolds group; while Lif-silencing BMSCs-loaded BCP scaffolds had the opposite effects. The present study for the first time demonstrated that LIF promoted the in vitro osteoblast differentiation of hypoxia-treated BMSCs; and further studies revealed that LIF exerted enhanced effects on the bone repair capacity of BMSCs-load BCP scaffolds in mouse calvarial bone defect model. However, future studies are warranted to determine the detailed mechanisms of LIF in the large-scale bone defect repair.

Hypoxia Enhanced Bone Regeneration Through the HIF-1α/β-Catenin Pathway in Femoral Head Osteonecrosis

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a common disease. Transplantation of bone marrow stem cells (BMSCs) is a promising method to treat ONFH but is impeded by the low survival rate and deficiency of cell bioactivity.

METHODS

We performed hypoxic preprocessing to treat BMSCs and assessed cell viability, apoptosis, differentiation, and growth factor expression in vitro. Subsequently, we constructed the ONFH model and delivered hypoxia-pretreated BMSCs to the rabbit femoral head after core decompression surgery, evaluating its effects on bone regeneration and ONFH repair. Six weeks later, micro-computed tomography (CT) and histopathology were performed to evaluate ONFH repair.

RESULTS

Our findings demonstrated that hypoxic preprocessing promoted the viability of BMSCs, increased the expression of hypoxia-inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor (VEGF), alkaline phosphatase (ALP), calcium deposition, and enhanced the formation of vessels-shaped structures. In an in vivo study, micro-CT observations demonstrated that the bone volume was increased in the hypoxia BMSCs group. Histological examination revealed reduced cellular apoptosis, lower empty lacunae rate, enhanced bone formation, and stronger trabecular bone in the hypoxia BMSCs group when compared with those transplanted with normoxia treated BMSCs. Additionally, immunological assessment of the hypoxia BMSCs group demonstrated increased expression of HIF-1α and β-catenin, as well as increased VEGF, ALP, osteocalcin (OCN), and collagen type I (Col-1).

CONCLUSIONS

Collectively, our findings indicated that hypoxia stimulated angiogenesis and bone regeneration via the HIF-1/β-catenin pathway in BMSCs and that the delivery of hypoxia-pretreated BMSCs contributed to the treatment of early ONFH.

MiR-181d-5p regulates implant surface roughness-induced osteogenic differentiation of bone marrow stem cells

Constructing moderate surface roughness is a widely used, non-toxic, cost-effective, and outcome-predictable approach to accelerate implant osteointegration in clinical settings. MicroRNAs (miRNAs) play vital regulatory roles in the osteogenic differentiation of bone marrow stem cells (BMSCs). However, their specific contribution to the influence of surface roughness on osteoblastic behavior remains unknown. Therefore, applying the smooth titanium surface as a control, a typical titanium surface with moderate roughness was prepared here to reveal the mechanism through which surface roughness regulates cell osteogenic behavior by altering miRNA expression. First, the morphology and roughness of two surfaces were characterized, and the enhanced osteogenic differentiation of BMSCs on rough surfaces was verified. Then, twenty-nine differentially expressed miRNAs in BMSCs cultured on different surfaces were selected via miRNA chip and corresponding functional prediction. After verifying the expression of these miRNAs using quantitative real-time polymerase chain reaction, four were considered eligible candidates. Among these, only miR-181d-5p significantly affected RUNX2 gene expression based on overexpression and knockdown experiments. From the osteogenesis-related gene and protein expression, as well as alkaline phosphatase and alizarin red experiments, we further confirmed that the downregulation of miR-181d-5p promoted osteogenic differentiation of BMSCs, and vice versa. In addition, rescue assays showed that the knockdown of miR-181d-5p improved the inferior osteogenesis observed on smooth surfaces, whereas the overexpression of miR-181d-5p suppressed the superior osteogenesis observed on rough surfaces. These results indicate that the moderate surface roughness of the implant stimulates the osteogenic differentiation of BMSCs by remarkably downregulating miR-181d-5p. These findings provide helpful information and a theoretical basis for the development of advanced implant materials for fast osteointegration.

Role of bone 1stem cell-seeded 3D polylactic acid/polycaprolactone/hydroxyapatite scaffold on a critical-sized radial bone defect in rat

Osteoconductive biomaterials were used to find the most reliable materials in bone healing. Our focus was on the bone healing capacity of the stem cell-loaded and unloaded PLA/PCL/HA scaffolds. The 3D scaffold of PLA/PCL/HA was characterized by scanning electron microscopy (SEM), rheology, X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) spectroscopy. Bone marrow stem cells (BMSCs) have multipotential differentiation into osteoblasts. Forty Wistar male rats were used to organize four experimental groups: control, autograft, scaffold, and BMSCs-loaded scaffold groups. qRT-PCR showed that the BMSCs-loaded scaffold had a higher expression level of CD31 and osteogenic markers compared with the control group (P < 0.05). Radiology and computed tomography (CT) scan evaluations showed significant improvement in the BMSCs-loaded scaffold compared with the control group (P < 0.001). Biomechanical estimation demonstrated significantly higher stress (P < 0.01), stiffness (P < 0.001), and ultimate load (P < 0.01) in the autograft and BMSCs-loaded scaffold groups compared with the untreated group and higher strain was seen in the control group than the other groups (P < 0.01). Histomorphometric and immunohistochemical (IHC) investigations showed significantly improved regeneration scores in the autograft and BMSCs-loaded scaffold groups compared with the control group (P < 0.05). Also, there was a significant difference between the scaffold and control groups in all tests (P < 0.05). The results depicted that our novel approach will allow to develop PLA/PCL/HA 3D scaffold in bone healing via BMSC loading.

Proliferative and Regenerative Effect of Acetonic Extract of Feijoa sellowiana on Stem Cells

BACKGROUND

Feijoa is widely used in medicine due to their anti-inflammatory, antioxidant, antimicrobial and antitumor properties. The current investigation studied the proliferative and regenerative effect of acetonic extract of Feijoa sellowiana on stem cells.

METHODS

Acetone extract of Feijoa was prepared using percolator and rotary machines. Human bone marrow stem cells (hBMSCs) were used as experimental in vitro model and characterized morphologically, by flowcytometry, and differentiation properties. The toxicity of the extract on hBMSCs was determined by MTT assay. The viability and growth kinetics of hBMSCs treated to Feijoa was determined. Real time PCR was used for changes in expression of proliferative and apoptotic genes on day 7^th.

RESULTS

MTT assay demondtrated that Feijoa at doses less than 200 ng/ml did not show any cytotoxic effect on hBMSCs and increased the cell proliferation until day 3^rd followed by a non-significant slow decreasing trend until day 7^th. Population doubling time (PDT) showed a decline until day 3^rd followed by an increase until day 7^th. A significant rise in expression of Bax and decline in Bcl-2 expression were noted on day 7^th.

CONCLUSION

The modulatory activity of Feijoa may be responsible for its increasing effect on cell proliferation till day 3^rd. Therefore, when faster proliferation during a shorter time period is targeted, Feijoa can be safely added to the culture media in the first three days.

Vascular Supply and Bone Marrow Concentrate for the Improvement of Allograft in Bone Defects: A Comparative In Vivo Study

BACKGROUND

Surgical repair of critical-sized bone defects still remains a big challenge in orthopedic surgery. Biological enhancement, such as growth factors or cells, can stimulate a better outcome in bone regeneration driven by well-established treatments such as allogenic bone graft. However, despite the surgical options available, correct healing can be slowed down or compromised by insufficient vascular supply to the injured site.

MATERIALS AND METHODS

In this pilot study, critical size bone defects in rabbit radius were treated with allograft bone, in combination with vascular bundle and autologous bone marrow concentrate seeded onto a commercial collagen scaffold. Microtomographical, histological and immunohistochemical assessments were performed to evaluate allograft integration and bone regeneration.

RESULTS

Results showed that the surgical deviation of vascular bundle in the bone graft, regardless from the addition of bone marrow concentrate, promote the onset of healing process at short experimental times (8 wk) in comparison with the other groups, enhancing graft integration.

CONCLUSION

The surgical procedure tested stimulates bone healing at early times, preserving native bone architecture, and can be easily combined with biological adjuvant.

Low magnitude high frequency vibration promotes chondrogenic differentiation of bone marrow stem cells with involvement of β-catenin signaling pathway

OBJECTIVE

Mesenchymal stem cells (MSCs) are well known to have the capability to form bone and cartilage, and chondrogenesis derived from MSCs is reported to be affected by mechanical stimuli. This research aimed to study the effects of low magnitude high frequency (LMHF) vibration on the chondrogenic differentiation of bone marrow-derived MSCs (BMSCs) which were cultured with chondrogenic medium, and to investigate the role of β-catenin cascade in this process.

METHODS

Rat bone marrow-derived MSCs (BMSCs) were isolated and randomized into vibration and static cultures. The effect of vibration on BMSCs proliferation, differentiation and chondrogenic potential was assessed at the protein level.

RESULTS

LMHFV did not affect the proliferation of BMSCs. However, this was accompanied by increased markers of chondrogenesis. The protein expression of chondrocyte-specific markers of Aggrecan, Sox9, and BMP7 were upregulated and Collagen X was decreased by LMHF vibration introduced at the chondrogenic differentiation in vitro. Specifically, thicker blue-stained particles were observed in Alcian Blue staining and the level of glycosaminoglycan were significantly increased respectively in the vibration culture group by 56.5 % and 93.6 % on the 7th and 14th day. The expression and nuclear translocation of β-catenin were activated in a significant manner. And inhibition of GSK-3β activity with Licl rearranged and intensified the cytoskeleton affected by vibration stimulation.

CONCLUSIONS

Our data demonstrated that LMHF mechanical vibration promotes BMSCs chondrogenic differentiation and implies β-catenin signal acts as an essential mediator in the mechano-biochemical transduction and subsequent transcriptional regulation in the process of chondrogenesis.

Nanocomposites drug delivery systems for the healing of bone fractures

The skeletal system is fundamental for the structure and support of the body consisting of bones, cartilage, and connective tissues. Poor fracture healing is a chief clinical problem leading to disability, extended hospital stays and huge financial liability. Even though most fractures are cured using standard clinical methods, about 10% of fractures are delayed or non-union. Despite decades of progress, the bone-targeted delivery system is still restricted due to the distinctive anatomical bone features. Recently, various novel nanocomposite systems have been designed for the cell-specific targeting of bone, enhancing drug solubility, improving drug stability and inhibiting drug degradation so that it can reach its target site without being removed in the systemic circulation. Such targeting systems could consist of biological compounds i.e. bone marrow stem cells (BMSc), growth factors, RNAi, parathyroid hormone or synthetic compounds, i.e. bisphosphonates (BPs) and calcium phosphate cement. Hydrogels and nanoparticles are also being employed for fracture healing. In this review, we discussed the normal mechanism of bone healing and all the possible drug delivery systems being employed for the healing of the bone fracture.

Rectification of radiotherapy-induced cognitive impairments in aged mice by reconstituted Sca-1+ stem cells from young donors

Background

Radiotherapy is widely used and effective for treating brain tumours, but inevitably impairs cognition as it arrests cellular processes important for learning and memory. This is particularly evident in the aged brain with limited regenerative capacity, where radiation produces irreparable neuronal damage and activation of neighbouring microglia. The latter is responsible for increased neuronal death and contributes to cognitive decline after treatment. To date, there are few effective means to prevent cognitive deficits after radiotherapy.

Methods

Here we implanted hematopoietic stem cells (HSCs) from young or old (2- or 18-month-old, respectively) donor mice expressing green fluorescent protein (GFP) into old recipients and assessed cognitive abilities 3 months post-reconstitution.

Results

Regardless of donor age, GFP⁺ cells homed to the brain of old recipients and expressed the macrophage/microglial marker, Iba1. However, only young cells attenuated deficits in novel object recognition and spatial memory and learning in old mice post-irradiation. Mechanistically, old recipients that received young HSCs, but not old, displayed significantly greater dendritic spine density and long-term potentiation (LTP) in CA1 neurons of the hippocampus. Lastly, we found that GFP⁺/Iba1⁺ cells from young and old donors were differentially polarized to an anti- and pro-inflammatory phenotype and produced neuroprotective factors and reactive nitrogen species in vivo, respectively.

Conclusion

Our results suggest aged peripherally derived microglia-like cells may exacerbate cognitive impairments after radiotherapy, whereas young microglia-like cells are polarized to a reparative phenotype in the irradiated brain, particularly in neural circuits associated with rewards, learning, and memory. These findings present a proof-of-principle for effectively reinstating central cognitive function of irradiated brains with peripheral stem cells from young donor bone marrow.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1681-3) contains supplementary material, which is available to authorized users.

Macrophage MSR1 promotes BMSC osteogenic differentiation and M2-like polarization by activating PI3K/AKT/GSK3β/β-catenin pathway

Approximately 10% of bone fractures do not heal satisfactorily, leading to significant clinical and socioeconomic implications. Recently, the role of macrophages in regulating bone marrow stem cell (BMSC) differentiation through the osteogenic pathway during fracture healing has attracted much attention. Methods: The tibial monocortical defect model was employed to determine the critical role of macrophage scavenger receptor 1 (MSR1) during intramembranous ossification (IO) in vivo. The potential functions and mechanisms of MSR1 were explored in a co-culture system of bone marrow-derived macrophages (BMDMs), RAW264.7 cells, and BMSCs using qPCR, Western blotting, immunofluorescence, and RNA sequencing. Results: In this study, using the tibial monocortical defect model, we observed delayed IO in MSR1 knockout (KO) mice compared to MSR1 wild-type (WT) mice. Furthermore, macrophage MSR1 mediated PI3K/AKT/GSK3β/β-catenin signaling increased ability to promote osteogenic differentiation of BMSCs in the co-culture system. We also identified proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) as the target gene for macrophage MSR1-activated PI3K/AKT/GSK3β/β-catenin pathway in the co-culture system that facilitated M2-like polarization by enhancing mitochondrial oxidative phosphorylation. Conclusion: Our findings revealed a previously unrecognized function of MSR1 in macrophages during fracture repair. Targeting MSR1 might, therefore, be a new therapeutic strategy for fracture repair.

Effects of intravitreal injection of human CD34+ bone marrow stem cells in a murine model of diabetic retinopathy

Human CD34 ⁺ stem cells are mobilized from bone marrow to sites of tissue ischemia and play an important role in tissue revascularization. This study used a murine model to test the hypothesis that intravitreal injection of human CD34 ⁺ stem cells harvested from bone marrow (BMSCs) can have protective effects in eyes with diabetic retinopathy. Streptozotocin-induced diabetic mice (C57BL/6J) were used as a model for diabetic retinopathy. Subcutaneous implantation of Alzet pump, loaded with Tacrolimus and Rapamycin, 5 days prior to intravitreal injection provided continuous systemic immunosuppression for the study duration to avoid rejection of human cells. Human CD34 ⁺ BMSCs were harvested from the mononuclear cell fraction of bone marrow from a healthy donor using magnetic beads. The CD34 ⁺ cells were labeled with enhanced green fluorescent protein (EGFP) using a lentiviral vector. The right eye of each mouse received an intravitreal injection of 50,000 EGFP-labeled CD34 ⁺ BMSCs or phosphate buffered saline (PBS). Simultaneous multimodal in vivo retinal imaging system consisting of fluorescent scanning laser ophthalmoscopy (enabling fluorescein angiography), optical coherence tomography (OCT) and OCT angiography was used to confirm the development of diabetic retinopathy and study the in vivo migration of the EGFP-labeled CD34 ⁺ BMSCs in the vitreous and retina following intravitreal injection. After imaging, the mice were euthanized, and the eyes were removed for immunohistochemistry. In addition, microarray analysis of the retina and retinal flat mount analysis of retinal vasculature were performed. The development of retinal microvascular changes consistent with diabetic retinopathy was visualized using fluorescein angiography and OCT angiography between 5 and 6 months after induction of diabetes in all diabetic mice. These retinal microvascular changes include areas of capillary nonperfusion and late leakage of fluorescein dye. Multimodal in vivo imaging and immunohistochemistry identified EGFP-labeled cells in the superficial retina and along retinal vasculature at 1 and 4 weeks following intravitreal cell injection. Microarray analysis showed changes in expression of 162 murine retinal genes following intravitreal CD34 ⁺ BMSC injection when compared to PBS-injected control. The major molecular pathways affected by intravitreal CD34 ⁺ BMSC injection in the murine retina included pathways implicated in the pathogenesis of diabetic retinopathy including Toll-like receptor, MAP kinase, oxidative stress, cellular development, assembly and organization pathways. At 4 weeks following intravitreal injection, retinal flat mount analysis showed preservation of the retinal vasculature in eyes injected with CD34 ⁺ BMSCs when compared to PBS-injected control. The study findings support the hypothesis that intravitreal injection of human CD34 ⁺ BMSCs results in retinal homing and integration of these human cells with preservation of the retinal vasculature in murine eyes with diabetic retinopathy.

A novel reporter construct for screening small molecule inhibitors that specifically target self-renewing cancer cells. Exp Cell Res. 2019;383:111551. [PMID: 31401066 DOI: 10.1016/j.yexcr.2019.111551]

Cancer stem cells (CSCs) are a subset of cancer cells, which possess self-renewal ability, and lead to tumor progression, metastasis, and resistance to therapy. Live detection and isolation of CSCs are important to understand the biology of CSCs as well as to screen drugs that target them. Even though CSCs are detected using surface markers, there is a lot of inconsistencies for that in a given cancer type. At the same time, self-renewal markers like ALDH1A1, OCT4A and SOX2, which are intracellular molecules, are reliable markers for CSCs in different cancers. In the present study, we generated a reporter construct for self-renewing CSCs, based on ALDH1A1 expression. Oral cancer cells harboring ALDH1A1-DsRed2 were used to screen inhibitors that target CSCs. Our results showed that Comb1, a cocktail of inhibitors for EGF and TGF-β pathways and their intermediates, effectively reduced the DsRed2 population to 34%. Our immunohistochemical analysis on primary oral cancer corroborated the importance of EGF and TGF-β pathways in sustaining CSCs. Since these two pathways are also critical for the self-renewal and differentiation of normal stem cells, Comb1 might abolish them as well. On analysis of the effect of Comb1 on normal murine bone marrow cells, there was no significant change in the stem cell self-renewal and differentiation potential in the treated group compared to untreated cells. To conclude, we claim that ALDH1A1-DsRed2 is a useful tool to detect CSCs, and Comb1 is effective in targeting CSCs without affecting normal stem cells.

Nerve growth factor gene therapy improves bone marrow sensory innervation and nociceptor-mediated stem cell release in a mouse model of type 1 diabetes with limb ischaemia

AIMS/HYPOTHESIS

Sensory neuropathy is common in people with diabetes; neuropathy can also affect the bone marrow of individuals with type 2 diabetes. However, no information exists on the state of bone marrow sensory innervation in type 1 diabetes. Sensory neurons are trophically dependent on nerve growth factor (NGF) for their survival. The aim of this investigation was twofold: (1) to determine if sensory neuropathy affects the bone marrow in a mouse model of type 1 diabetes, with consequences for stem cell liberation after tissue injury; and (2) to verify if a single systemic injection of the NGF gene exerts long-term beneficial effects on these phenomena.

METHODS

A mouse model of type 1 diabetes was generated in CD1 mice by administration of streptozotocin; vehicle was administered to non-diabetic control animals. Diabetic animals were randomised to receive systemic gene therapy with either human NGF or β-galactosidase. After 13 weeks, limb ischaemia was induced in both groups to study the recovery post injury. When the animals were killed, samples of tissue and peripheral blood were taken to assess stem cell mobilisation and homing, levels of substance P and muscle vascularisation. An in vitro cellular model was adopted to verify signalling downstream to human NGF and related neurotrophic or pro-apoptotic effects. Normally distributed variables were compared between groups using the unpaired Student's t test and non-normally distributed variables were assessed by the Wilcoxon-Mann-Whitney test. The Fisher's exact test was employed for categorical variables.

RESULTS

Immunohistochemistry indicated a 3.3-fold reduction in the number of substance P-positive nociceptive fibres in the bone marrow of type 1 diabetic mice (p < 0.001 vs non-diabetic). Moreover, diabetes abrogated the creation of a neurokinin gradient which, in non-diabetic mice, favoured the mobilisation and homing of bone-marrow-derived stem cells expressing the substance P receptor neurokinin 1 receptor (NK1R). Pre-emptive gene therapy with NGF prevented bone marrow denervation, contrasting with the inhibitory effect of diabetes on the mobilisation of NK1R-expressing stem cells, and restored blood flow recovery from limb ischaemia. In vitro hNGF induced neurite outgrowth and exerted anti-apoptotic actions on rat PC12 cells exposed to high glucose via activation of the canonical neurotrophic tyrosine kinase receptor type 1 (TrkA) signalling pathway.

CONCLUSIONS/INTERPRETATION

This study shows, for the first time, the occurrence of sensory neuropathy in the bone marrow of type 1 diabetic mice, which translates into an altered modulation of substance P and depressed release of substance P-responsive stem cells following ischaemia. NGF therapy improves bone marrow sensory innervation, with benefits for healing on the occurrence of peripheral ischaemia. Nociceptors may represent a new target for the treatment of ischaemic complications in diabetes.

CD133+ bone marrow stem cells (BMSC) control platelet activation - Role of ectoNTPDase-1 (CD39)

BACKGROUND

We previously demonstrated CD133+ bone marrow stem cells (BMSC) to promote hepatic proliferation for liver regeneration. Here, we evaluated the capacity of CD133+BMSC to utilize platelets for homing to vasculature and concomitant controlling their aggregability upon ADP stimulation.

METHODS

CD133+BMSC and platelets were co-cultured along micro endothelial cells under variable flow conditions and tested for homing levels along vasculature. Aggregometry and FACS analysis were utilized to evaluate platelet reactivity following co-incubation ± CD133+BMSC. RT-PCR and FACS analyses served to characterize ADP degrading ectonucleoside triphosphate diphosphohydrolase-1 (ectoNTPDase-1/CD39) expression on various cell types.

RESULTS

Platelets attracted human CD133+BMSC to autologous micro endothelium under shear stress unaffected by ADP stimulation. However, CD133+BMSC inhibited ADP-mediated platelet activation and aggregation. Latter was dependent on ectoNTPDase-1 expression levels. Platelet aggregatory control was increased with CD133+BMSC compared to CD133+PHSC. Different effects of those stem cell subtypes positively correlated with their FACS-detected expression levels of ectoNTPDase-1.

CONCLUSION

We provide evidence that CD133+BMSC are capable of controlling ADP-dependent platelet aggregation and activation by direct interaction dependent on cellular expression of ectoNTPDase-1. Whether different capacities of BMSC modulate platelet-depending thrombogenicity at sites of regeneration impact effectiveness and adverse event profiles of regenerative treatment requires further evaluation.

Down-regulation of miR-122 after transplantation of mesenchymal stem cells in acute liver failure in mice model

This study investigated the correlation between the hepatic level of miR-122 and the extent of liver tissue regeneration in CCl₄ induced liver injury mice model following transplantation of menstrual blood-(MenSCs) and bone marrow-derived stem cells (BMSCs). Hepatic miR-122 levels were significantly up-regulated following administration of CCl₄ (P < 0.01). The significant positive correlations were observed between hepatic miR-122 and biochemical serum markers and the severity of liver injury in histopathological assessments (P < 0.01). Following stem cell therapy, all cell treated groups showed a significant down-regulation in miR-122 that was significantly correlated with improvement in histopathological features and biochemical markers (P < 0.01). Furthermore, the hepatic level of miR-122 was lower in the MenSCs-treated group compared with the BMSCs-treated group (P < 0.01) and in HPL cells-treated groups in reference to undifferentiated cells-treated groups (P < 0.05). These data suggest that miR-122 could be used as a potential predictor of outcome of liver injury after mesenchymal stem cell transplantation.

Runx1 regulates osteogenic differentiation of BMSCs by inhibiting adipogenesis through Wnt/β-catenin pathway

OBJECTIVE

Bone marrow stem cells (BMSCs) can commit to both adipocyte and osteoblast lineages. However, the mechanism underlying how transcription factors regulate this process remains elusive. Our aims were to determine the role of runt-related transcription factor 1 (Runx1) in BMSCs lineage determination and the underlying mechanisms.

STUDY DESIGN

BMSCs from mouse femur bone marrow were harvested and cultured in osteogenic medium. Runx1 was knocked down in BMSCs using lentivirus. Alkaline phosphatase (ALP), Von Kossa and Oil Red O staining were performed on the Runx1-transduced BMSCs and control cells to see the differences of osteogenic and adipogenic differentiation in these groups. Real-time quantitative PCR and Western blot were performed to analyse the expression levels of osteogenic and adipogenic factors regulated by Runx1 at gene and protein levels.

RESULTS

In BMSCs with Runx1 knockdown, the expression levels of osteogenic-related genes decreased significantly while the adipogenic genes C/EBPα, PPARγ and Fabp4 increased by 12-fold, 10-fold, and 30-fold, respectively, compared with the control cells. ALP activity and Von kossa staining were greatly decreased in Runx1-transfected cells while the Oil Red O staining was comparable to that in the control groups. Canonical Wnt signaling was investigated in the Runx1-deficient BMSCs, and a 50% decrease in the expression of active β-catenin in these cells was found. Lef1 and Tcf1, which are regulated by β-catenin were also decreased in Runx1-deficient cells compared with the levels in controls. Moreover, although there was no difference in the expression of Wnt3a among the three groups of cells, the expression of Wnt10b decreased by 80% in Runx1-deficient BMSCs compared with the levels in the other two groups.

CONCLUSIONS

Our results show Runx1 promotes the capacity of osteogenesis in BMSCs while inhibits their adipogenesis through canonical Wnt/β-catenin pathway, which provides new insights into osteoblast development.

Performing a Better Bone Marrow Aspiration

Bone marrow aspiration (BMA) is increasingly being used to harvest stem cells for use in regenerative medicine. The focus of BMA in interventional orthopedics is to maximize the yield of mesenchymal stem cells. The authors present an improved method for BMA that involves fluoroscope or ultrasound guidance combined with anesthesia; in the authors' experience, it produces the highest possible stem cell yield and is well tolerated by patients. The authors provide a step-by-step guide to the process, along with a discussion of technical and other considerations and quick reference guides for ultrasound- and fluoroscope-guided BMA.

Stromal-Cell-Derived Factor (SDF) 1-Alpha Overexpression Promotes Bone Regeneration by Osteogenesis and Angiogenesis in Osteonecrosis of the Femoral Head

BACKGROUND/AIMS

Osteonecrosis of the femoral head (ONFH) is a devastating orthopedic disease. Previous studies suggested that stromal-cell-derived factor (SDF)-1 was involved in osteogenesis and angiogenesis. However, whether SDF-1 potentiates the angiogenesis and osteogenesis of bone marrow-derived stromal stem cells (BMSCs) in ONFH is not clear.

METHODS

BMSCs were transfected with green fluorescent protein (GFP) or the fusion gene encoding GFP and SDF-1α, and transgenic efficacy was monitored by immunofluorescence. The expression of SDF-1α, runt-related transcription factor 2 (Runx2, osteocalcin (OCN), and alkaline phosphatase (ALP) at the mRNA level was measured by real-time polymerase chain reactions (RT-PCR). The expression of SDF-1α, Runx2, OCN, and p-Smad1/5 were measured at the protein level by Western blot. Transwell migration assay and tube formation assay were utilized to detect the angiogenesis in vitro, whereas the in vivo angiogenesis was monitored by angiography. Immunohistological staining and micro-CT scanning were conducted to assess the histological changes in morphology.

RESULTS

In vitro, SDF-1α overexpression in BMSCs promoted osteogenic differentiation and upregulated the expression of osteogenic-related proteins, such as ALP, Runx2, OCN, and p-Smadl/5. In the methylprednisolone induced ONFH rat model used in our investigation, the overexpression of SDF-1α in BMSCs promoted significantly more bone regeneration and the expression of OCN and Runx2 as compared with the effect of vehicle overexpression. Moreover, the morphology of ONFH was ameliorated after the transplantation of BMSCs with SDF-1α overexpression. Furthermore, SDF-1α overexpression in BMSCs significantly increased osteoblastic angiogenesis as indicated by the increased tube formation ability, CD31 expression, and vessel volume.

CONCLUSION

SDF-1α overexpression in BMSCs promotes bone generation as indicated by osteogenesis and angiogenesis, suggesting SDF-1α may serve as a therapeutic drug target for ONFH treatment.

Differentiation Potential of Mesenchymal Stem Cells Derived from Adipose Tissue vs Bone Marrow Toward Annulus Fibrosus Cells In vitro

BACKGROUND

Bone marrow stem cells (BMSCs) and adipose-derived stem cells (ADSCs) are two types of stem cells that commonly used in exogenous tissue engineering as well as endogenous tissue repair, however which type of cell is superior remains unknown.

OBJECTIVE

This study was conducted to compare differentiation potential of BMSCs and ADSCs from Sprague-Dawley rats towards annulus fibrosus (AF)-like cells.

METHOD

Stem cells and AF cells were cocultured with direct cell-to-cell contact in coculture plates with 0.4m pore size up till 21 days. AF markers expression at the histological level and molecular level were evaluated by histological analysis and dimethplmethplene blue (DMMB) assay as well as quantitative reverse-transcription polymerase chain reaction (qRT-PCR).

RESULTS

qRT-PCR) results showed up regulation in AF marker gene expressions of both two MSCs after coculture. BMSCs demonstrated a statistically increased expression of collagen II and aggrecan from 7 days of coculture. However, these gene expressions in ADSCs showed a statistically increase at day 14 and day 21. And there was a statistically increase of Collagen I expression in BMSCs at 14 days and 21 days. But only after 21 days of coculture, ADSCs showed a statistically increase in collagen I expression. Moreover, histological analysis and dimethplmethplene blue (DMMB) assay mirrored the results of qRT-PCR. Morphologically, BMSCs became enlarged and triangular, while ADSCs were enlarged and rounded after coculture.

CONCLUSION

These findings suggested that BMSCs might be superior as a cell source for annulus fibrosus repair compared to ADSCs.

Chronic stress induced duration dependent alterations in immune system and their reversibility in rats

The objective was to find out whether severity of stress effects on immunity increases with duration of exposure and recovery depends on duration of exposure. Adult male rats (n = 30) were subjected to restraint (1 h) followed by forced swimming exercise (15 min) after a gap of 4 h daily for 2, 4 and 8 weeks and allowed to recover for 6 weeks after each exposure period. Exposure of rats to stress resulted in duration dependent significant decreases in leukocyte count, phagocytic indices of neutrophils, number of bone marrow stem cells and serum levels of IL-12 and increases in apoptotic index of peripheral blood mononuclear cells and serum levels of IL-10. The alterations in counts of neutrophils, total immunoglobulin content, phagocytic index, apoptotic index of peripheral blood mononuclear cells and serum levels of IL-10 returned to control levels in recovery group rats of 2 and 4 weeks exposure but not in that of 8 weeks exposure. However, alterations in number and apoptotic index of bone marrow stem cells returned to control levels in 2, 4 and 8 weeks stress recovery groups. The results for the first time reveal that increase in duration of exposure results in more severe damage in immune system and that shorter the exposure period, faster the recovery. In addition, in vitro study for the first time showed that corticosterone causes apoptosis of peripheral blood mononuclear cells and bone marrow stem cells in dose dependent manner. Hence death of leukocytes and their stem cells is the major cause of stress induced immune dysfunction.

Intrathecal Autologous Bone Marrow-Derived Hematopoietic Stem Cell Therapy in Neurological Diseases

BACKGROUND

Cellular transplantation is a promising treatment strategy for neurological diseases.

OBJECTIVE

To report the results of intrathecal hematopoietic stem cell therapy in different neurological diseases in the past 6 years in a single center.

METHODS

From October 2011 to September 2018, 220 patients with various neurological diseases were transplanted intrathecally by their bone marrow stem cells. To have a longer follow up, we only reported the first 80 patients, transplanted up to July 2015-10 patients had spinal cord injuries and paralysis, 12 had advanced Parkinson's disease, 28 had cerebral palsy, 7 had hypoxic brain damage, 2 had autism, 4 had multiple sclerosis, 5 had progressive cerebellar atrophy, and 12 had other neurological diseases. The patients were admitted to the Bone Marrow Transplant Unit. On the first day, 50-200 (median 100) mL bone marrow was aspirated from the patients' posterior iliac crests, mixed with 120 mL culture media (RPMI), and 12 mL heparin. The samples were then transferred to immunology lab in cold box. Mononuclear cells (MNCs) were separated by a Ficoll-Hypaque gradient, washed, and suspended in ringers. Cell viability was assessed with trypan blue viability test. Transplantation was performed 3-4 hours after bone marrow collection. 5-10 mL of the cerebrospinal fluids were aspirated and about 20 mL MNCs (containing stem cells) in ringers were injected intrathecally (IT). The patients were laid down on their back for 4-5 hours. The median number of MNCs was 4×10⁷ (range 1-450×10⁷). The median viability of the cells was 90% (range 60%-98%). The patients received intravenous ceftriaxone every 12 hours and were discharged from the hospital few days after autologous stem cell therapy.

RESULTS

We noted clinical improvements in 9 of 12 patients with Parkinson's disease, 20 of 28 patients with cerebral palsy, 6 of 7 patients with hypoxic brain damage, 2 of 4 patients with multiple sclerosis, and 4 of 5 patients with cerebellar atrophy. The improvements were noted after 2-4 weeks of cell therapy. There were no improvements in patients with spinal cord injury and complete paralysis and those with autism. There were variable improvements in other patients treated.

CONCLUSION

Most patients with advanced Parkinson's disease, cerebral palsy, hypoxic brain damage, progressive cerebellar atrophy, and kernicterus neuropathy reported clinical effects of this safe intervention resulting in better functioning and an increased quality of life.

Direct comparison of the abilities of bone marrow mesenchymal versus hematopoietic stem cells to reverse hyperglycemia in diabetic NOD.SCID mice

Both bone marrow-derived hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC) improve glycemic control in diabetic mice, but their kinetics and associated changes in pancreatic morphology have not been directly compared. Our goal was to examine the time course of improvements in glucose tolerance and associated changes in β-cell mass and proliferation following transplantation of equivalent numbers of HSC or MSC from the same bone marrow into diabetic non-obese diabetic severe combined immune deficiency (NOD.SCID) mice. We used transgenic mice with a targeted expression of yellow fluorescent protein (YFP) driven by the Vav1 gene promoter to genetically tag HSC and progeny. HSC were separated from bone marrow by fluorescence-activated cell sorting and MSC following cell culture. Equivalent numbers of isolated HSC or MSC were transplanted directly into the pancreas of NOD.SCID mice previously made diabetic with streptozotocin. Glucose tolerance, serum insulin, β-cell mass and β-cell proliferation were examined up to 28 days following transplant. Transplantation with MSC improved glucose tolerance within 7 days and serum insulin levels increased, but with no increase in β-cell mass. Mice transplanted with HSC showed improved glucose tolerance only after 3 weeks associated with increased β-cell proliferation and mass. We conclude that single injections of either MSC or HSC transiently improved glycemic control in diabetic NOD.SCID mice, but with different time courses. However, only HSC infiltrated the islets and were associated with an expanded β-cell mass. This suggests that MSC and HSC have differing mechanisms of action.

Single-stage treatment of infected tibial non-unions and osteomyelitis with bone marrow granulocytes precursors protecting bone graft

PURPOSE

Infected non-unions present a clinical challenge, especially with risk of recurrent infection. Bone marrow contains granulocyte precursors identified in vitro as colony forming units-granulocyte macrophage (CFU-GM) have a prophylactic action against infection. We therefore tested the hypothesis that bone marrow concentrated granulocytes precursors added to a standard bone graft could decrease the risk of recurrence of infection when single-stage treatment of infected tibial non-unions is performed with bone graft.

METHODS

During a single-stage procedure 40 patients with infected tibial non-union received a spongious bone graft supercharged with granulocytes precursors after debridement (study group). A control group (40 patients) was treated in a single stage with local debridement and standard bone graft obtained from the iliac crest. The antibiotic therapy protocol was the same (60 days) in the two groups. CFU-GM progenitors were harvested from bone marrow aspirated on the opposite iliac crest of the site where the cancellous bone was obtained. Union (radiographs and CT scan), a recurrence of clinical infection, and need for subsequent surgery were evaluated.

RESULTS

Thirty-eight (95%) patients who received graft supercharged with granulocytes precursors achieved successful union without recurrence of infection during the seven-year follow-up versus 28 (70%) control patients; for the control group the mean graft resorption volume was 40%, while no bone graft resorption was found for the study group.

CONCLUSION

Supercharging the cancellous bone graft with bone marrow granulocytes precursors protect the site of infected non-union from recurrence of infection and bone resorption of the graft.

CXCR4 enhances invasion and proliferation of bone marrow stem cells via PI3K/AKT/NF-κB signaling pathway

Osteosarcoma is the most common type of cancer that develops in bone, specifically; it is an aggressive malignant neoplasm. The purpose of this study is using superparamagnetic iron oxide nanoparticles (SPION) labeled bone mesenchymal stem cells (MSCs) to migrate into cancerous parts, then using alternating magnetic field to produce the high temperature to kill cancer cells in vitro. In order to enhance the invasion ability of MSCs, we successfully overexpressed CXCR4 in MSCs, we found the invasion behavior of CXCR4 overexpressed MSCs and CXCR4 overexpressed SPION labeled MSCs was enhanced when compared with MSCs. In addition, the proliferation of CXCR4 overexpressed MSCs and CXCR4 overexpressed SPION labeled MSCs. Then, we found that CXCR4 was able to enhance invasion related genes expression, including MMP9, MMP2, MMP13, MMP7, MMP10, MMP8, and MMP1. Among these genes, MMP9 and MMP2 were associated with PI3K/AKT/NF-κB signaling. The expression of MMP9 and MMP2 was decreased when PI3K/AKT signaling inhibitor LY294002 and NF-κB inhibitor PDTC were used respectively. Moreover the migrated of CXCR4 overexpressed MSCs and CXCR4 overexpressed SPION labeled MSCs were significantly reduced after LY294002 and PDTC used. These results suggest that CXCR4 overexpressed SPION labeled MSCs can be more easier migrate into cancerous parts; it may provide a promising method to treat the osteosarcoma.

MicroRNA-21 promotes bone mesenchymal stem cells migration in vitro by activating PI3K/Akt/MMPs pathway

MicroRNA-21 (miR-21) contributes to anti-apoptosis in bone marrow mesenchymal stem cells (BMSC), but its role in the migration of BMSCs remains vague. The aim of this study was to determine the possible effect of miR-21 on regulating BMSCs directional migration and the expression of MMP-2/MMP-9 in BMSCs in vitro. BMSCs were successfully infected with miR-21-up lentivirus. Cell migration using Transwell assay indicated that upregulated expression of miR-21 could significantly promote BMSCs migration. Western blot analysis indicated that miR-21 significantly upregulated the expression of MMP-2 and MMP-9, which were related to metastasis-associated genes. GM6001, the specific MMPs inhibitor, abrogated the upregulated expression of MMP-2/MMP-9 and abolished the positive effect of miR-21 on promoting BMSCs migration. Meanwhile, miR-21 significantly enhanced Akt phosphorylation, as measured by Western blot analysis. LY294002, an inhibitor of Akt activation, abrogated the phosphorylation of Akt and abolished the positive effect of miR-21 on promoting BMSCs migration and upregulating MMP-2/MMP-9 expression. These results suggest that miR-21 contributes to BMSCs migration by upregulating MMP-2/MMP-9, potentially via the PI3K/Akt pathway.

Chondrogenesis of human bone marrow mesenchymal stem cells in 3-dimensional, photocrosslinked hydrogel constructs: Effect of cell seeding density and material stiffness

Three-dimensional hydrogel constructs incorporated with live stem cells that support chondrogenic differentiation and maintenance offer a promising regenerative route towards addressing the limited self-repair capabilities of articular cartilage. In particular, hydrogel scaffolds that augment chondrogenesis and recapitulate the native physical properties of cartilage, such as compressive strength, can potentially be applied in point-of-care procedures. We report here the synthesis of two new materials, [poly-l-lactic acid/polyethylene glycol/poly-l-lactic acid] (PLLA-PEG 1000) and [poly-d,l-lactic acid/polyethylene glycol/poly-d,l-lactic acid] (PDLLA-PEG 1000), that are biodegradable, biocompatible (>80% viability post fabrication), and possess high, physiologically relevant mechanical strength (∼1500 to 1800kPa). This study examined the effects of physiologically relevant cell densities (4, 8, 20, and 50×10⁶/mL) and hydrogel stiffnesses (∼150kPa to∼1500kPa Young's moduli) on chondrogenesis of human bone marrow stem cells incorporated in hydrogel constructs fabricated with these materials and a previously characterized PDLLA-PEG 4000. Results showed that 20×10⁶cells/mL, under a static culture condition, was the most efficient cell seeding density for extracellular matrix (ECM) production on the basis of hydroxyproline and glycosaminoglycan content. Interestingly, material stiffness did not significantly affect chondrogenesis, but rather material concentration was correlated to chondrogenesis with increasing levels at lower concentrations based on ECM production, chondrogenic gene expression, and histological analysis. These findings establish optimal cell densities for chondrogenesis within three-dimensional cell-incorporated hydrogels, inform hydrogel material development for cartilage tissue engineering, and demonstrate the efficacy and potential utility of PDLLA-PEG 1000 for point-of-care treatment of cartilage defects.

STATEMENT OF SIGNIFICANCE

Engineering cartilage with physiologically relevant mechanical properties for point-of-care applications represents a major challenge in orthopedics, given the generally low mechanical strengths of traditional hydrogels used in cartilage tissue engineering. In this study, we characterized a new material that possesses high mechanical strength similar to native cartilage, and determined the optimal cell density and scaffold stiffness to achieve the most efficient chondrogenic response from seeded human bone marrow stem cells. Results show robust chondrogenesis and strongly suggest the potential of this material to be applied clinically for point-of-care repair of cartilage defects.

Application of Bone Marrow Stem Cell Based Therapy in Bone Loss Diseases

Hematopoietic bone marrow stem cell transplantation has been regularly used in clinical practice for over 40 years. Further research indicates that bone marrow stromal cells are also stem cells that are capable of self-renewal, proliferation and differentiation. With appropriate induction, the bone marrow stromal cells can differentiate into bone, cartilage, tendon, adipose tissue and fibrous tissue, which would potentially be applied for treating bone loss diseases. This review outlines research in understanding role of bone marrow stem cells and stem cells from other origins in bone repair, and highlight the current and potential stem cell based treatment for bone loss diseases in the future.

Fifteen years of bone marrow mononuclear cell therapy in acute myocardial infarction

In spite of modern treatment, acute myocardial infarction (AMI) still carries significant morbidity and mortality worldwide. Even though standard of care therapy improves symptoms and also long-term prognosis of patients with AMI, it does not solve the critical issue, specifically the permanent damage of cardiomyocytes. As a result, a complex process occurs, namely cardiac remodeling, which leads to alterations in cardiac size, shape and function. This is what has driven the quest for unconventional therapeutic strategies aiming to regenerate the injured cardiac and vascular tissue. One of the latest breakthroughs in this regard is stem cell (SC) therapy. Based on favorable data obtained in experimental studies, therapeutic effectiveness of this innovative therapy has been investigated in clinical settings. Of various cell types used in the clinic, autologous bone marrow derived SCs were the first used to treat an AMI patient, 15 years ago. Since then, we have witnessed an increasing body of data as regards this cutting-edge therapy. Although feasibility and safety of SC transplant have been clearly proved, it’s efficacy is still under dispute. Conducted studies and meta-analysis reported conflicting results, but there is hope for conclusive answer to be provided by the largest ongoing trial designed to demonstrate whether this treatment saves lives. In the meantime, strategies to enhance the SCs regenerative potential have been applied and/or suggested, position papers and recommendations have been published. But what have we learned so far and how can we properly use the knowledge gained? This review will analytically discuss each of the above topics, summarizing the current state of knowledge in the field.

Mesenchymal stem cell therapy in Parkinson's disease animal models

Parkinson's disease is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra, and as a consequence, by decreased dopamine levels in the striatum. Currently available therapies are not able to stop or reverse the progression of the disease. A novel therapeutic approach is based on cell therapy with stem cells, in order to replace degenerated neurons. Among stem cells, mesenchymal stem cells seemed the most promising thanks to their capacities to differentiate toward dopaminergic neurons and to release neurotrophic factors. Indeed, mesenchymal stem cells are able to produce different molecules with immunomodulatory, neuroprotective, angiogenic, chemotactic effects and that stimulate differentiation of resident stem cells. Mesenchymal stem cells were isolated for the first time from bone marrow, but can be collected also from adipose tissue, umbilical cord and other tissues. In this review, we focused our attention on mesenchymal stem cells derived from different sources and their application in Parkinson's disease animal models.

G-CSF-mobilized Bone Marrow Mesenchymal Stem Cells Replenish Neural Lineages in Alzheimer's Disease Mice via CXCR4/SDF-1 Chemotaxis

Recent studies reported granulocyte colony-stimulating factor (G-CSF) treatment can improve the cognitive function of Alzheimer's disease (AD) mice, and the mobilized hematopoietic stem cells (HSCs) or bone marrow mesenchymal stem cells (BM-MSCs) are proposed to be involved in this recovery effect. However, the exact role of mobilized HSC/BM-MSC in G-CSF-based therapeutic effects is still unknown. Here, we report that C-X-C chemokine receptor type 4 (CXCR4)/stromal cell-derived factor 1 (SDF-1) chemotaxis was a key mediator in G-CSF-based therapeutic effects, which was involved in the recruitment of repair-competent cells. Furthermore, we found both mobilized HSCs and BM-MSCs were able to infiltrate into the brain, but only BM-MSCs replenished the neural lineage cells and contributed to neurogenesis in the brains of AD mice. Together, our data show that mobilized BM-MSCs are involved in the replenishment of neural lineages following G-CSF treatment via CXCR4/SDF-1 chemotaxis and further support the potential use of BM-MSCs for further autogenically therapeutic applications.

Injectable calcium phosphate with hydrogel fibers encapsulating induced pluripotent, dental pulp and bone marrow stem cells for bone repair

Human induced pluripotent stem cell-derived mesenchymal stem cells (hiPSC-MSCs), dental pulp stem cells (hDPSCs) and bone marrow MSCs (hBMSCs) are exciting cell sources in regenerative medicine. However, there has been no report comparing hDPSCs, hBMSCs and hiPSC-MSCs for bone engineering in an injectable calcium phosphate cement (CPC) scaffold. The objectives of this study were to: (1) develop a novel injectable CPC containing hydrogel fibers encapsulating stem cells for bone engineering, and (2) compare cell viability, proliferation and osteogenic differentiation of hDPSCs, hiPSC-MSCs from bone marrow (BM-hiPSC-MSCs) and from foreskin (FS-hiPSC-MSCs), and hBMSCs in CPC for the first time. The results showed that the injection did not harm cell viability. The porosity of injectable CPC was 62%. All four types of cells proliferated and differentiated down the osteogenic lineage inside hydrogel fibers in CPC. hDPSCs, BM-hiPSC-MSCs, and hBMSCs exhibited high alkaline phosphatase, runt-related transcription factor, collagen I, and osteocalcin gene expressions. Cell-synthesized minerals increased with time (p<0.05), with no significant difference among hDPSCs, BM-hiPSC-MSCs and hBMSCs (p>0.1). Mineralization by hDPSCs, BM-hiPSC-MSCs, and hBMSCs inside CPC at 14d was 14-fold that at 1d. FS-hiPSC-MSCs were inferior in osteogenic differentiation compared to the other cells. In conclusion, hDPSCs, BM-hiPSC-MSCs and hBMSCs are similarly and highly promising for bone tissue engineering; however, FS-hiPSC-MSCs were relatively inferior in osteogenesis. The novel injectable CPC with cell-encapsulating hydrogel fibers may enhance bone regeneration in dental, craniofacial and orthopedic applications.

miR-145 Regulates Diabetes-Bone Marrow Stromal Cell-Induced Neurorestorative Effects in Diabetes Stroke Rats

In rats with type 1 diabetes mellitus (T1DM) subject to stroke, the therapeutic effects and underlying mechanisms of action of bone-marrow stromal cells (BMSCs) derived from T1DM rats (DM-BMSCs) and BMSCs derived from normal rats (Nor-BMSCs) were compared. In vitro and in vivo, DM-BMSCs exhibited decreased miR-145 expression. In T1DM rats, DM-BMSC treatment significantly improved functional outcome and increased vascular and white matter remodeling. However, overexpression of miR-145 in DM-BMSCs attenuates DM-BMSC-induced neurorestorative effects in T1DM stroke rats.

In rats with type 1 diabetes (T1DM), the therapeutic effects and underlying mechanisms of action of stroke treatment were compared between bone-marrow stromal cells (BMSCs) derived from T1DM rats (DM-BMSCs) and BMSCs derived from normal rats (Nor-BMSCs). The novel role of microRNA-145 (miR-145) in mediating DM-BMSC treatment-induced benefits was also investigated. T1DM rats (n = 8 per group) underwent 2 hours of middle cerebral artery occlusion (MCAo) and were treated 24 hours later with the one of the following (5 × 10⁶ cells administered i.v.): (a) phosphate-buffered saline (PBS); (b) Nor-BMSCs; (c) DM-BMSCs; (d) DM-BMSCs with miR-145 overexpression (miR-145+/+DM-BMSCs); or (e) Nor-BMSCs with miR-145 knockdown. Evaluation of functional outcome, vascular and white-matter remodeling and microRNA expression was made, and in vitro studies were performed. In vitro, DM-BMSCs exhibited decreased miR-145 expression and increased survival compared with Nor-BMSCs. Capillary tube formation and axonal outgrowth in cultured primary cortical neurons were significantly increased by DM-BMSC-conditioned medium compared with Nor-BMSCs, and significantly decreased by miR-145+/+DM-BMSC-conditioned medium compared with DM-BMSCs. In T1DM rats in which stroke had been induced (T1DM stroke rats), DM-BMSC treatment significantly improved functional outcome, increased vascular and white matter remodeling, decreased serum miR-145 expression, and increased expression of the miR-145 target genes adenosine triphosphate-binding cassette transporter 1 (ABCA1) and insulin-like growth factor 1 receptor (IGFR1), compared with Nor-BMSCs or PBS treatment. However, miR-145+/+DM-BMSCs significantly increased serum miR-145 expression and decreased brain ABCA1 and IGFR1 expression, as well as attenuated DM-BMSC-induced neurorestorative effects in T1DM-MCAo rats. DM-BMSCs exhibited decreased miR-145 expression. In T1DM-MCAo rats, DM-BMSC treatment improved functional outcome and promoted neurorestorative effects. The miR-145/ABCA1/IGFR1 pathway may contribute to the enhanced DM-BMSCs’ functional and neurorestorative effects in T1DM stroke rats.

Significance

In rats with type 1 diabetes (T1DM), the therapeutic effects and underlying mechanisms of action of stroke treatment were compared between bone-marrow stromal cells (BMSCs) derived from T1DM rats (DM-BMSCs) and BMSCs derived from normal rats (Nor-BMSCs). In vitro, DM-BMSCs and derived exosomes decreased miR-145 expression and increased DM-BMSC survival, capillary tube formation, and axonal outgrowth, compared with Nor-BMSCs; these effects were decreased by DM-BMSCs in which miR-145 was overexpressed. In vivo, compared with Nor-BMSC or phosphate-buffered saline treatment, DM-BMSC treatment improved functional outcome and vascular and white matter remodeling, decreased serum miR-145 expression, and increased expression of the miR-145 target genes ABCA1 and IGFR1. microRNA-145 mediated the benefits induced by DM-BMSC treatment.