Qian Hou

Multiple intravenous infusions of bone marrow mesenchymal stem cells reverse hyperglycemia in experimental type 2 diabetes rats

The worldwide rapid increase in diabetes poses a significant challenge to current therapeutic approaches. Single-dose mesenchymal stem cell (MSC) infusion ameliorates hyperglycemia but fails to restore normoglycemia in diabetic animals. We therefore hypothesized that multiple intravenous MSC infusions may reverse hyperglycemia in type 2 diabetes (T2D) rats. We administered serial allogenous bone-marrow derived MSC infusions (1 × 10(6)cells/infusion) via the tail vein once every 2 weeks to T2D rats, induced by high-fat diet and streptozocin (STZ) administration. Hyperglycemia decreased only transiently after a single infusion in early-phase (1 week) T2D rats, but approximated normal levels after at least three-time infusions. This normal blood level was maintained for at least 9 weeks. Serum concentrations of both insulin and C-peptide were dramatically increased after serial MSC infusions. Oral glucose tolerance tests revealed that glucose metabolism was significantly ameliorated. Immunofluorescence analysis of insulin/glucagon staining revealed the restoration of islet structure and number after multiple MSC treatments. When multiple-MSC treatment was initiated in late-phase (5 week) T2D rats, the results were slightly different. The results of this study suggested that a multiple-MSC infusion strategy offers a viable clinical option for T2D patients.

Hypoxia Pretreatment of Bone Marrow Mesenchymal Stem Cells Facilitates Angiogenesis by Improving the Function of Endothelial Cells in Diabetic Rats with Lower Ischemia

Endothelial dysfunction induced by unordered metabolism results in vascular reconstruction challenges in diabetic lower limb ischemia (DLLI). Mesenchymal stem cells (MSCs) are multipotent secretory cells that are suitable for clinical DLLI treatment, but their use has been hampered by poor survival after injection. Hypoxia can significantly enhance the capacity of MSCs to secrete angiogenic factors. We investigated transient hypoxia pretreatment of MSCs to facilitate revascularization in DLLI. Rat bone marrow MSCs (BM-MSCs) were cultured at different oxygen concentrations for varying time periods. The results indicated that transient pretreatment (5% O2, 48 h) not only increased the expression of VEGF-1α, ANG, HIF-1α and MMP-9 in BM-MSCs as assessed by real-time RT-PCR, but also increased the expression of Bcl-2 as determined by western blotting. The transplantation of pretreated BM-MSCs into rats with DLLI demonstrated accelerated vascular reconstruction when assayed by angiography and immunohistochemistry. CM-Dil-labeled tracer experiments indicated that the survival of BM-MSCs was significantly improved, with approximately 5% of the injected cells remaining alive at 14 days. The expression levels of VEGF-1α, MMP-9 and VEGF-R were significantly increased, and the expression of pAKT was up-regulated in ischemic muscle. Double immunofluorescence studies confirmed that the pretreated BM-MSCs promoted the proliferation and inhibited the apoptosis of endothelial cells. In vitro, pretreated BM-MSCs increased the migratory and tube forming capacity of endothelial cells (ECs). Hypoxia pretreatment of BM-MSCs significantly improved angiogenesis in response to tissue ischemia by ameliorating endothelial cell dysfunction and is a promising therapeutic treatment for DLLI.

Hypoxia pretreatment of bone marrow-derived mesenchymal stem cells seeded in a collagen-chitosan sponge scaffold promotes skin wound healing in diabetic rats with hindlimb ischemia.

Bone marrow—derived mesenchymal stem cells (BM‐MSCs) have properties that make them promising for the treatment of chronic nonhealing wounds. The major challenge is ensuring an efficient, safe, and painless delivery of BM‐MSCs. Tissue‐engineered skin substitutes have considerable benefits in skin damage resulting from chronic nonhealing wounds. Here, we have constructed a three‐dimensional biomimetic scaffold known as collagen‐chitosan sponge scaffolds (CCSS) using the cross‐linking and freeze‐drying method. Scanning electron microscopy images showed that CCSS had an interconnected network pore configuration about 100 μm and exhibited a suitable swelling ratio for maintaining morphological stability and appropriate biodegradability to improve biostability using swelling and degradation assays. Furthermore, BM‐MSCs were seeded in CCSS using the two‐step seeding method to construct tissue‐engineered skin substitutes. In addition, in this three‐dimensional biomimetic CCSS, BM‐MSCs secreted their own collagen and maintain favorable survival ability and viability. Importantly, BM‐MSCs exhibited a significant upregulated expression of proangiogenesis factors, including HIF‐1α, VEGF, and PDGF following hypoxia pretreatment. In vivo, hypoxia pretreatment of the skin substitute observably accelerated wound closure via the reduction of inflammation and enhanced angiogenesis in diabetic rats with hindlimb ischemia. Thus, hypoxia pretreatment of the skin substitutes can serve as ideal bioengineering skin substitutes to promote optimal diabetic skin wound healing.

Treatment of MSCs with Wnt1a-conditioned medium activates DP cells and promotes hair follicle regrowth

Hair loss (alopecia) is a common problem for people. The dermal papilla is the key signaling center that regulates hair growth and it engage in crosstalk with the microenvironment, including Wnt signaling and stem cells. In this study, we explored the effects of bone marrow mesenchymal stem cell overexpression of Wnt1a on mouse hair follicle regeneration. Wnt-CM accelerated hair follicle progression from telogen to anagen and enhanced the ALP expression in the DP area. Moreover, the hair induction-related genes were upregulated, as demonstrated by qRT-PCR. Wnt-CM treatment restored and increased DP cell expression of genes downregulated by dihydrotestosterone treatment, as demonstrated by qRT-PCR assays. Our study reveals that BM-MSC-generated Wnt1a promotes the DPs ability to induce hair cycling and regeneration.

Transdifferentiation of Umbilical Cord- Derived Mesenchymal Stem Cells Into Epidermal-Like Cells by the Mimicking Skin Microenvironment

Human umbilical cord–derived mesenchymal stem cells (UC-MSCs) are multipotent, primitive, and have been widely used for skin tissue engineering. Their transdifferentiation is determined by the local microenvironment. In this study, we investigated the potential epidermal differentiation of UC-MSCs and the formation of epidermis substitutes in a 3-dimensional (3D) microenvironment, which was fabricated by UC-MSCs embedded into collagen–chitosan scaffolds (CCSs) combined with an air–liquid interface (ALI) culture system. Using fluorescence microscope, we observed that UC-MSCs were spindle-shaped and evenly distributed in the scaffold. Methyl thiazolyl blue tetrazolium bromide assay and Live/Dead assay indicated that the CCSs have good biocompatibility with UC-MSCs. Immunohistochemistry and western blotting assay showed that UC-MSCs on the surface of the CCSs were positive for the epidermal markers cytokeratin 19 and involucrin at 14 days. In addition, hematoxylin–eosin staining indicated that multilayered epidermis substitutes were established. The constructed epidermis substitutes were applied to treat full-thickness wounds in rats and proved to promote wound healing. In conclusion, manipulating the 3D microenvironment is a novel method for inducing the epidermal differentiation of MSCs to engineer epidermal substitutes, which provides an alternative strategy for skin tissue engineering.

The Four-Herb Chinese Medicine ANBP Enhances Wound Healing and Inhibits Scar Formation via Bidirectional Regulation of Transformation Growth Factor Pathway

The four-herb Chinese medicine ANBP is a pulverized mixture of four herbs including Agrimonia Eupatoria (A), Nelumbo Nucifera Gaertn (N), Boswellia Carteri (B) and Pollen Typhae Angustifoliae (P). The combination of the four herbs was first described in Chinese canonical medicine about 2000 years ago for treatment of various trauma disorders, such as hemostasis, antiinflammatory, analgesia, and wound healing, etc. However, the precise mechanisms of ANBP are still unclear. In our study, using rabbit ear hypertrophic scar models of full-thickness skin defect, we showed that local ANBP treatment not only significantly enhanced wound healing by relieving inflammation, increasing formation of granulation tissue and accelerating re-epithelialization, but also reduced scar formation by decreasing collagen production, protuberant height and volume of scars, and increasing collagen maturity. We demonstrated that these effects of ANBP are associated with transforming growth factor (TGF)-β1-mediated signalling pathways through Smad-dependent pathways. ANBP treatment significantly increased expression of TGF-β1 and Smad2/3 mRNA at the early stage of wound healing, and led to markedly decrease expression of TGF-β1 and Smad2/3 compared with the control group after 14 days post-wounding. Taken together, our results defined a bidirectional regulation role of ANBP for TGF-β1/Smad pathway in promoting wound healing and alleviating scar formation, which may be an effective therapy for human wounds at the earliest stage.

Pharmacokinetic interaction between tacrolimus and berberine in a child with idiopathic nephrotic syndrome

Berberine is a major isoquinoline alkaloid in herbs such as goldenseal, berberis, and Coptis chinensis and has been traditionally used to treat diarrhea [1]. We report here a welldocumented interaction between tacrolimus and berberine in a child with idiopathic nephrotic syndrome. A 16-year-old child was confirmed to have nephrotic syndrome after observation of 1-month history of generalized edema associated with persistent proteinuria in April 2012. The immunosuppressive therapy was initialed with prednisone (60 mg/m/day), frequent relapses occurs when prednisone dose was reduced to 40 mg/m/day. Tacrolimus (0.1 mg/kg, twice daily) was then added to immunosuppressive therapy. Tacrolimus dosage adjustment was based on therapeutic drug monitoring (TDM) in order to maintain trough blood concentration (C0) in the therapeutic range of 5–15 ng/mL [2]. Blood tacrolimus concentrations were measured using an enzymemultiplied immunoassay technique (EMIT). In October 2012, tacrolimus was given at the dose of 6.5 mg twice daily. As the child developed diarrhea, berberine (0.2 g three times daily) was started. Tacrolimus C0 and increased from 8 to 22 ng*mL, while serum creatinine increased from 62 to 109 μmol*L. Therefore, daily dose of tacrolimus was decreased to 3 mg and after 5 days, C0 was 12 ng*mL , while serum creatinine decreased to 84 μmol*L. The review of the medical chart did not allow identification of any other known factors (liver function, infection) that might explain such increase in tacrolimus concentrations and none of the other associated drugs are known to interact with tacrolimus metabolism and disposition. Polymorphisms of CYP3A4 (*1B), CYP3A5 (*3) and ABCB1 (C3435T) were determined using TaqMan allelic discrimination technique. Pharmacogenotyping results indicated that our patient was homozygous wild type for CYP3A4*1B, homozygous mutated (*3/*3) for CYP3A5, homozygous mutated for C3435T (T/T). To our knowledge, our report demonstrates for the first time that berberine strongly affects the disposition of tacrolimus, with clinically relevant increase in tacrolimus C0 concentrations and renal toxicity. Berberine is an inhibitor of CYP3A4. It has been reported to increase cyclosporine concentration in renal transplant adults and midazolam concentrations in adult healthy volunteers [3, 4]. The individual pharmacogenetic profile of our patient might be helpful for interpreting the significant tacrolimus–berberine interaction. This observation implies drug–drug interaction in both drug metabolism and transport. Our patient is deficient for CYP3A5 genes, CYP3A4 pathway became predominant. Furthermore, the patient was homozygous mutated C3435T (T/T) for transporter ABCB1, leading to a significantly reduced ABCB1 expression. The competition between the two drugs occurs also at the CYP3A4 pathway, resulting in high tacrolimus concentrations. We report a significant in vivo interaction between tacrolimus and berberine, both substrates of CYP3A4-A5, resulting in rapid increase in tacrolimus blood concentrations. Berberine is currently used for the treatment of diarrhea. Careful monitoring of tacrolimus blood concentrations and Q. Hou :W. Han (*) :X. Fu (*) Institute of Basic Medicine, School of Life Sciences, Chinese PLA General Hospital, Beijing 100853, People’s Republic of China e-mail: hanwdrsw69@yahoo.com e-mail: fu_ys@yahoo.cn

Pluripotent reprogramming and lineage reprogramming: promises and challenges in cardiovascular regeneration.

Cardiovascular disease is a leading cause of death in industrialized countries. Scientists are trying to generate cardiomyocytes in vitro and in vivo to repair damaged heart tissue. Pluripotent reprogramming brings an alternative source of embryonic-like stem cells, and the possibility of regenerating mammalian tissues by first reverting somatic cells to induced pluripotent stem cells, followed by redifferentiating these cells into cardiomyocytes. More recently, lineage reprogramming of fibroblasts directly into functional cardiomyocytes has been reported. The procedure does not involve reverting cells back to a pluripotent stage, and, thus, would presumably reduce tumorigenic potential. Interestingly, lineage reprogramming could be used for in situ conversion of cell fate. Moreover, zebrafish-like regenerative mechanism in mammalian heart tissue, which was observed in mice within the first week of postpartum, should be further addressed. Here, we review the landmark progresses of the two major reprogramming strategies, compare their pros and cons in cardiovascular regeneration, and forecast the future directions of cardiac repair.

A Conditioned Medium of Umbilical Cord Mesenchymal Stem Cells Overexpressing Wnt7a Promotes Wound Repair and Regeneration of Hair Follicles in Mice

Mesenchymal stem cells (MSCs) can affect the microenvironment of a wound and thereby accelerate wound healing. Wnt proteins act as key mediators of skin development and participate in the formation of skin appendages such as hair. The mechanisms of action of MSCs and Wnt proteins on skin wounds are largely unknown. Here, we prepared a Wnt7a-containing conditioned medium (Wnt-CM) from the supernatant of cultured human umbilical cord-MSCs (UC-MSCs) overexpressing Wnt7a in order to examine the effects of this CM on cutaneous healing. Our results revealed that Wnt-CM can accelerate wound closure and induce regeneration of hair follicles. Meanwhile, Wnt-CM enhanced expression of extracellular matrix (ECM) components and cell migration of fibroblasts but inhibited the migratory ability and expression of K6 and K16 in keratinocytes by enhancing expression of c-Myc. However, we found that the CM of fibroblasts treated with Wnt-CM (HFWnt-CM-CM) can also promote wound repair and keratinocyte migration; but there was no increase in the number of hair follicles of regeneration. These data indicate that Wnt7a and UC-MSCs have synergistic effects: they can accelerate wound repair and induce hair regeneration via cellular communication in the wound microenvironment. Thus, this study opens up new avenues of research on the mechanisms underlying wound repair.

Effects of the Four-Herb Compound ANBP on Wound Healing Promotion in Diabetic Mice

Wound healing is a troublesome problem in diabetic patients. Besides, there is also an increased risk of postsurgical wound complications for diabetic patient. It has been revealed that traditional Chinese medicine may promote healing and inhibit scar formation, while the changes of morphology and physiology of wounds on such medicine treatment still remain elusive. In this study, we first used the ultralow temperature preparation method to produce mixed superfine powder from Agrimonia pilosa (A), Nelumbo nucifera (N), Boswellia carteri (B), and Pollen typhae (P), named as ANBP. Applying ANBP on 40 streptozotocin (STZ)-induced diabetic C57BL/6 mice (4-6 weeks, 20 ± 2 g), we observed that the wound healing process was accelerated and the wound healing time was shortened (14 days, P < .05). Pathological observation using hematoxylin–eosin staining indicated that inflammatory cells were reduced (P < .05) while the thickness of granulation tissue and length of epithelial tongue were increased (P < .05). The vascular density was increased on 7 and 14 days after ANBP treatment. Masson and Sirius red staining showed that, at the early stage of trauma, the expressions of Col I and Col III, especially Col III, were increased in the ANBP group (P < .05). Studies in vitro demonstrated that tubular formation was significantly increased after ANBP treatment on human vascular endothelial cells in a dose-dependent way. Taken together, our studies revealed that ANBP treatment could accelerate wound healing, promote vascularization, and inhibit inflammation, suggesting the potential clinic application of ANBP for diabetes mellitus and refractory wounds.