Endothelial progenitor cell therapy for chronic wound tissue regeneration

Angio-microRNAs in diabetic foot ulcer-: Mechanistic insights and clinical perspectives

Diabetic foot ulcers, as one of the chronic wounds, are a serious challenge in the global healthcare system which have shown notable growth in recent years. DFU is associated with impairment in various stages of wound healing, including angiogenesis. Aberrant expression of microRNAs (miRNAs) involved in the disruption of the balance between angiogenic and anti-angiogenic factors, plays a crucial role in angiogenesis dysfunction. Alteration in the expression of angiomiRNAs (angiomiRs) have the potential to function as biomarkers in chronic wounds. Additionally, considering the rising importance of therapeutic RNAs, there is potential for utilizing angiomiRs in wound healing to induce angiogenesis. This review aims to explore angiogenesis in chronic wounds and investigate the mechanisms mediated by pro- and anti-angiomiRs in the context of diabetic foot ulcers.

3D Porous Polymer Scaffold-Conjugated KGF-Mimetic Peptide Promotes Functional Skin Regeneration in Chronic Diabetic Wounds

The re-epithelialization process gets severely dysregulated in chronic nonhealing diabetic foot ulcers/wounds. Keratinocyte growth factor (KGF or FGF-7) is the major modulator of the re-epithelialization process, which regulates the physiological phenotypes of cutaneous keratinocytes. The existing therapeutic strategies of growth factor administration have several limitations. To overcome these, we have designed a KGF-mimetic peptide (KGFp, 13mer) based on the receptor interaction sites in murine KGF. KGFp enhanced migration and transdifferentiation of mouse bone marrow-derived MSCs toward keratinocyte-like cells (KLCs). A significant increase in the expression of skin-specific markers Bnc1 (28.5-fold), Ck5 (14.6-fold), Ck14 (26.1-fold), Ck10 (187.7-fold), and epithelial markers EpCam (23.3-fold) and Cdh1 (64.2-fold) was associated with the activation of ERK1/2 and STAT3 molecular signaling in the KLCs. Further, to enhance the stability of KGFp in the wound microenvironment, it was conjugated to biocompatible 3D porous polymer scaffolds without compromising its active binding sites followed by chemical characterization using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, dynamic mechanical analysis, and thermogravimetry. In vitro evaluation of the KGFp-conjugated 3D polymer scaffolds revealed its potential for transdifferentiation of MSCs into KLCs. Transplantation of allogeneic MSCGFP using KGFp-conjugated 3D polymer scaffolds in chronic nonhealing type 2 diabetic wounds (db/db transgenic, 50-52 weeks old male mice) significantly enhanced re-epithelialization-mediated wound closure rate (79.3%) as compared to the control groups (Untransplanted -22.4%, MSCGFP-3D polymer scaffold -38.5%). Thus, KGFp-conjugated 3D porous polymer scaffolds drive the fate of the MSCs toward keratinocytes that may serve as potential stem cell delivery platform technology for tissue engineering and transplantation.

The Angiogenic Repertoire of Stem Cell Extracellular Vesicles: Demystifying the Molecular Underpinnings for Wound Healing Applications

Stem cells-derived extracellular vesicles (SC-EVs) have emerged as promising therapeutic agents for wound repair, recapitulating the biological effects of parent cells while mitigating immunogenic and tumorigenic risks. These EVs orchestrate wound healing processes, notably through modulating angiogenesis-a critical event in tissue revascularization and regeneration. This study provides a comprehensive overview of the multifaceted mechanisms underpinning the pro-angiogenic capacity of EVs from various stem cell sources within the wound microenvironment. By elucidating the molecular intricacies governing their angiogenic prowess, we aim to unravel the mechanistic repertoire underlying their remarkable potential to accelerate wound healing. Additionally, methods to enhance the angiogenic effects of SC-EVs, current limitations, and future perspectives are highlighted, emphasizing the significant potential of this rapidly advancing field in revolutionizing wound healing strategies.

TLQP-21 facilitates diabetic wound healing by inducing angiogenesis through alleviating high glucose-induced injuries on endothelial progenitor cells

Diabetes mellitus (DM) is a metabolic disease with multiple complications, including diabetic cutaneous wounds, which lacks effective treating strategies and severely influences the patients' life. Endothelial progenitor cells (EPCs) are reported to participate in maintaining the normal function of blood vessels, which plays a critical role in diabetic wound healing. TLQP-21 is a VGF-derived peptide with promising therapeutic functions on DM. Herein, the protective effects of TLQP-21 on diabetic cutaneous wound and the underlying mechanism will be investigated. Cutaneous wound model was established in T2DM mice, followed by administering 120 nmol/kg and 240 nmol/kg TLQP-21 once a day for 12 days. Decreased wound closure, reduced number of capillaries and EPCs, declined tube formation function of EPCs, and inactivated PI3K/AKT/eNOS signaling in EPCs were observed in T2DM mice, which were sharply alleviated by TLQP-21. Normal EPCs were extracted from mice and stimulated by high glucose (HG), followed by incubated with TLQP-21 in the presence or absence of LY294002, an inhibitor of PI3K. The declined cell viability, increased apoptotic rate, reduced number of migrated cells, declined migration distance, repressed tube formation function, and inactivated PI3K/AKT/eNOS signaling observed in HG-treated EPCs were markedly reversed by TLQP-21, which were dramatically abolished by the co-culture of LY294002. Collectively, TLQP-21 facilitated diabetic wound healing by inducing angiogenesis through alleviating HG-induced injuries on EPCs.

Silencing of transient receptor potential canonical channel 4 inhibits endothelial progenitor cell angiogenesis by suppressing VEGF and SDF-1

OBJECTIVES

Endothelial progenitor cells (EPCs) play a crucial role in acquired angiogenesis and endothelial injury repair. Transient receptor potential canonical channel 4 (TRPC4), a key component of store-operated calcium channels, is essential for EPC function. While the role of TRPCs has been clarified in vascular diseases, the relationship between TRPC4 and EPC function, along with the underlying molecular mechanisms, remains unclear and requires further elucidation.

METHODS

EPCs were isolated from canine bone marrow and identified by morphology and flow cytometry. TRPC4 was transfected into EPCs using lentivirus or negative control, and its expression was assessed using real-time polymerase chain reaction (RT-PCR). Proliferation, migration, and tube formation were evaluated using Cell Counting Kit-8 (CCK-8), Transwell, and Matrigel assays, respectively. Levels of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1) were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

TRPC4 mRNA expression was significantly reduced in TRPC4-short hairpin RNA (shRNA) transfected EPCs compared to the normal control (NC)-shRNA groups. Migration and tube formation were significantly decreased after TRPC4 silencing, while proliferation showed no difference. Additionally, levels of SDF-1 and VEGF in EPCs were markedly reduced following TRPC4 silencing.

CONCLUSION

TRPC4 plays a crucial role in regulating angiogenesis in EPCs. Silencing of TRPC4 can lead to decreased angiogenesis by inhibiting VEGF and SDF-1 expression, suggesting that TRPC4 knockdown might be a novel therapeutic strategy for vascular diseases.

Topical delivery of insulin using novel organogel formulations: An approach for the management of diabetic wounds

Diabetes mellitus is a growing chronic form of diabetes, with lengthy health implications. It is predicted as poor diabetic wound recovery affects roughly 25% of all diabetes mellitus patients, frequently resulting in lower traumatic injury and severe external factors and emotional expenses. The insulin-resistant condition increases biofilm development, making diabetic wounds harder to treat. Nowadays, medical treatment and management of diabetic wounds, which have a significant amputation rate, a high-frequency rate, and a high death rate, have become a global concern. Topical formulations have played a significant part in diabetic wound management and have been developed to achieve a number of features. Because of its significant biocompatibility, moisture retention, and therapeutic qualities, topical insulin has emerged as an appealing and feasible wound healing process effector. With a greater comprehension of the etiology of diabetic wounds, numerous functionalized topical insulins have been described and shown good outcomes in recent years, which has improved some diabetic injuries. The healing of wounds is a physiological phenomenon that restores skin integrity and heals damaged tissues. Insulin, a powerful wound-healing factor, is also used in several experimental and clinical studies accelerate healing of diverse injuries.

Phosphoenolpyruvate carboxykinase-1 targeted siRNA promotes wound healing in type 2 diabetic mice by restoring glucose homeostasis

It is well-accepted that the liver plays a vital role in the metabolism of glucose and its homeostasis. Dysregulated hepatic glucose production and utilization, leads to type 2 diabetes (T2DM). In the current study, RNA sequencing and qRT-PCR analysis of nanoformulation-treated T2DM mice (TGthr group) revealed beneficial crosstalk of PCK-1 silencing with other pathways involved in T2DM. The comparison of precise genetic expression profiles of the different experimental groups showed significantly improved hepatic glucose, fatty acid metabolism and several other T2DM-associated crucial markers after the nanoformulation treatment. As a result of these improvements, we observed a significant acceleration in wound healing and improved insulin signaling in vascular endothelial cells in the TGthr group as compared to the T2DM group. Enhanced phosphorylation of PI3K/Akt pathway proteins in the TGthr group resulted in increased angiogenesis as observed by the increased expression of endothelial cell markers (CD31, CD34) thereby improving endothelial dysfunctions in the TGthr group. Additionally, therapeutic nanoformulation has been observed to improve the inflammatory cytokine profile in the TGthr group. Overall, our results demonstrated that the synthesized therapeutic nanoformulation referred to as GPR8:PCK-1siRNA holds the potential in ameliorating hyperglycemia-associated complications such as delayed wound healing in diabetes.

Epidermal Stem Cell Derived Exosomes Alleviate Excessive Autophagy Induced Endothelial Cell Apoptosis by Delivering miR200b-3p to Diabetic Wounds

The dysfunction of endothelial cells caused by hyperglycemia is observed as a decrease in neovascularization in diabetic wound healing. Studies have found that epidermal stem cells (EpiSCs) can promote the angiogenesis of full-thickness wounds. To further explain the therapeutic effect of EpiSCs, EpiSC-derived exosomes (EpiSC-EXOs) are considered the main substance contributing to stem cell effectivity. In our study, EpiSCs and EpiSC-EXOs were supplied to the dorsal wounds of db/db mice. Results showed that EpiSCs could colonize in the wound area and both EpiSCs and EpiSC-EXOs could accelerate diabetic wound healing by promoting angiogenesis. In vitro, persistent high glucose led to the malfunction and apoptosis of endothelial cells. The apoptosis induced by high glucose is due to excessive autophagy and was alleviated by EpiSC-EXOs. RNA sequencing of EpiSC-EXOs showed that miR200b-3p was enriched in EpiSC-EXOs and alleviated the apoptosis of endothelial cells. Synapse defective rho GTPase homolog 1 was identified the target of miR200b-3p and affected the phosphorylation of ERK to regulate intracellular autophagy and apoptosis. Furthermore, animal experiments validated the angiogenic effect of miR200b-3p. Collectively, our results verified the effect of EpiSC-EXOs on apoptosis caused by hyperglycemia in endothelial cells through the miR200b-3p/synapse defective rho GTPase homolog 1 /RAS/ERK/autophagy pathway, providing a theoretical basis for EpiSC in treating diabetic wounds.

Nrf2 activation: a key mechanism in stem cell exosomes-mediated therapies

Exosomes are nano-sized membrane extracellular vesicles which can be released from various types of cells. Exosomes originating from inflammatory or injured cells can have detrimental effects on recipient cells, while exosomes derived from stem cells not only facilitate the repair and regeneration of damaged tissues but also inhibit inflammation and provide protective effects against various diseases, suggesting they may serve as an alternative strategy of stem cells transplantation. Exosomes have a fundamental role in communication between cells, through the transfer of proteins, bioactive lipids and nucleic acids (like miRNAs and mRNAs) between cells. This transfer significantly impacts both the physiological and pathological functions of recipient cells. Nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor, is able to mitigate damage caused by oxidative stress and inflammation through various signaling pathways. The positive effects resulting from the activation of the Nrf2 signaling pathway in different disorders have been documented in various types of literature. Studies have confirmed that exosomes derived from stem cells could act as Nrf2 effective agonists. However, limited studies have explored the Nrf2 role in the therapeutic effects of stem cell-derived exosomes. This review provides a comprehensive overview of the existing knowledge concerning the role of Nrf2 signaling pathways in the impact exerted by stem cell exosomes in some common diseases.

The role of endothelial cell-pericyte interactions in vascularization and diseases

BACKGROUND

Endothelial cells (ECs) and pericytes (PCs) are crucial components of the vascular system, with ECs lining the inner layer of blood vessels and PCs surrounding capillaries to regulate blood flow and angiogenesis. Intercellular communication between ECs and PCs is vital for the formation, stability, and function of blood vessels. Various signaling pathways, such as the vascular endothelial growth factor/vascular endothelial growth factor receptor pathway and the platelet-derived growth factor-B/platelet-derived growth factor receptor-β pathway, play roles in communication between ECs and PCs. Dysfunctional communication between these cells is associated with various diseases, including vascular diseases, central nervous system disorders, and certain types of cancers.

AIM OF REVIEW

This review aimed to explore the diverse roles of ECs and PCs in the formation and reshaping of blood vessels. This review focused on the essential signaling pathways that facilitate communication between these cells and investigated how disruptions in these pathways may contribute to disease. Additionally, the review explored potential therapeutic targets, future research directions, and innovative approaches, such as investigating the impact of EC-PCs in novel systemic diseases, addressing resistance to antiangiogenic drugs, and developing novel antiangiogenic medications to enhance therapeutic efficacy.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Disordered EC-PC intercellular signaling plays a role in abnormal blood vessel formation, thus contributing to the progression of various diseases and the development of resistance to antiangiogenic drugs. Therefore, studies on EC-PC intercellular interactions have high clinical relevance.

Retinoic acid signaling in development and differentiation commitment and its regulatory topology

Retinoic acid (RA), the derivative of vitamin A/retinol, is a signaling molecule with important implications in health and disease. It is a well-known developmental morphogen that functions mainly through the transcriptional activity of nuclear RA receptors (RARs) and, uncommonly, through other nuclear receptors, including peroxisome proliferator-activated receptors. Intracellular RA is under spatiotemporally fine-tuned regulation by synthesis and degradation processes catalyzed by retinaldehyde dehydrogenases and P450 family enzymes, respectively. In addition to dictating the transcription architecture, RA also impinges on cell functioning through non-genomic mechanisms independent of RAR transcriptional activity. Although RA-based differentiation therapy has achieved impressive success in the treatment of hematologic malignancies, RA also has pro-tumor activity. Here, we highlight the relevance of RA signaling in cell-fate determination, neurogenesis, visual function, inflammatory responses and gametogenesis commitment. Genetic and post-translational modifications of RAR are also discussed. A better understanding of RA signaling will foster the development of precision medicine to improve the defects caused by deregulated RA signaling.

Endothelial progenitor cells systemic administration alleviates multi-organ senescence by down-regulating USP7/p300 pathway in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has impacted approximately 390 million people worldwide and the morbidity is increasing every year. However, due to the poor treatment efficacy of COPD, exploring novel treatment has become the hotpot of study on COPD. Endothelial progenitor cells (EPCs) aging is a possible molecular way for COPD development. We aimed to explore the effector whether intravenous administration of EPCs has therapeutic effects in COPD mice.

METHODS

COPD mice model was induced by cigarette smoke exposure and EPCs were injected intravenously to investigate their effects on COPD mice. At day 127, heart, liver, spleen, lung and kidney tissues of mice were harvested. The histological effects of EPCs intervention on multiple organs of COPD mice were detected by morphology assay. Quantitative real-time PCR and Western blotting were used to detect the effect of EPCs intervention on the expression of multi-organ senescence-related indicators. And we explored the effect of EPCs systematically intervening on senescence-related USP7/p300 pathway.

RESULTS

Compared with COPD group, senescence-associated β-galactosidase activity was decreased, protein and mRNA expression of p16 was down-regulated, while protein and mRNA expression of cyclin D1 and TERT were up-regulated of multiple organs, including lung, heart, liver, spleen and kidney in COPD mice after EPCs system intervention. But the morphological alterations of the tissues described above in COPD mice failed to be reversed. Mechanistically, EPCs systemic administration inhibited the expression of mRNA and protein of USP7 and p300 in multiple organs of COPD mice, exerting therapeutic effects.

CONCLUSIONS

EPCs administration significantly inhibited the senescence of multiple organs in COPD mice via down-regulating USP7/p300 pathway, which presents a possibility of EPCs therapy for COPD.

Sonic hedgehog signaling promotes angiogenesis of endothelial progenitor cells to improve pressure ulcers healing by PI3K/AKT/eNOS signaling

BACKGROUND

Pressure ulcer is a severe disease in the paralyzed and aging populations. Endothelial progenitor cells (EPCs) are able to regulate ulcer healing by modulating angiogenesis, but the molecular mechanism is still obscure. Sonic hedgehog (SHH) signaling contributes to angiogenesis in various diseases and has been identified to modulate EPCs function. Here, we aimed to explore the significance of SHH signaling in EPCs function during pressure ulcers.

METHODS

The EPCs were isolated and characterized by the expression of DiI-acLDL and bind fluorescein iso-thiocyanate UEA-1. Cell proliferation was detected by cell counting kit 8 (CCK-8). The DiI-acLDL and bind fluorescein iso-thiocyanate UEA-1 were analyzed by immunofluorescent analysis. The angiogenesis of EPCs was analyzed by tube formation assay. The pressure ulcers rat model was constructed, the wound injury was analyzed by H&E staining and angiogenesis was analyzed by the accumulation of CD31 based on immunofluorescent analysis.

RESULTS

The expression of patched-1 and Gli-1 was enhanced by SHH activator SAG but reduced by SHH inhibitor cyclopamine in the EPCsThe PI3K, Akt, eNOS expression and the Akt phosphorylation were induced by SAG, while the treatment of cyclopamine presented a reversed result. The proliferation and migration of EPCs were enhanced by SAG but repressed by cyclopamine or PI3K/AKT/eNOS signaling inhibitor Y294002, in which the co-treatment of Y294002 could reverse the effect of SAG.

CONCLUSIONS

Thus, we found that SHH signaling activated angiogenesis properties of EPCs to improve pressure ulcers healing by PI3K/AKT/eNOS signaling. SHH signaling may serve as the potential target for attenuating pressure ulcers.

Tissue engineered skin substitutes: A comprehensive review of basic design, fabrication using 3D printing, recent advances and challenges

The multi-layered skin structure includes the epidermis, dermis and hypodermis, which forms a sophisticated tissue composed of extracellular matrix (ECM). The wound repair is a well-orchestrated process when the skin is injured. However, this natural wound repair will be ineffective for large surface area wounds. Autografts-based treatment is efficient but, additional pain and secondary healing of the patient limits its successful application. Therefore, there is a substantial need for fabricating tissue-engineered skin constructs. The development of a successful skin graft requires a fundamental understanding of the natural skin and its healing process, as well as design criteria for selecting a biopolymer and an appropriate fabrication technique. Further, the fabrication of an appropriate skin graft needs to meet physicochemical, mechanical, and biological properties equivalent to the natural skin. Advanced 3D bioprinting provides spatial control of the placement of functional components, such as biopolymers with living cells, which can satisfy the prerequisites for the preparation of an ideal skin graft. In this view, here we elaborate on the basic design requirements, constraints involved in the fabrication of skin graft and choice of ink, the probable solution by 3D bioprinting technique, as well as their latest advancements, challenges, and prospects.

Neuropeptide substance P: A promising regulator of wound healing in diabetic foot ulcers

In the past, neuropeptide substance P (SP) was predominantly recognized as a neuroinflammatory factor, while its potent healing activity was overlooked. This paper aims to review the regulatory characteristics of neuropeptide SP in both normal and diabetic wound healing. SP actively in the regulation of wound healing-related cells directly and indirectly, exhibiting robust inflammatory properties, promoting cell proliferation and migration and restoring the activity and paracrine ability of skin cells under diabetic conditions. Furthermore, SP not only regulates healing-related cells but also orchestrates the immune environment, thereby presenting unique and promising application prospects in wound intervention. As new SP-based preparations are being explored, SP-related drugs are poised to become an effective therapeutic intervention for diabetic foot ulcers (DFU).

A Multifunctional Polyethylene Glycol/Triethoxysilane-Modified Polyurethane Foam Dressing with High Absorbency and Antiadhesion Properties Promotes Diabetic Wound Healing

The delayed healing of chronic wounds, such as diabetic foot ulcers (DFUs), is a clinical problem. Few dressings can promote wound healing by satisfying the demands of chronic wound exudate management and tissue granulation. Therefore, the aim of this study was to prepare a high-absorption polyurethane (PU) foam dressing modified by polyethylene glycol (PEG) and triethoxysilane (APTES) to promote wound healing. PEG-modified (PUE) and PEG/APTES-modified (PUESi) dressings were prepared by self-foaming reactions. Gauze and PolyMem were used as controls. Next, Fourier transform-infrared spectroscopy, thermomechanical analyses, scanning electron microscopy and tensile strength, water absorption, anti-protein absorption, surface dryness and biocompatibility tests were performed for in vitro characterization. Wound healing effects were further investigated in nondiabetic (non-DM) and diabetes mellitus (DM) rat models. The PUE and PUESi groups exhibited better physicochemical properties than the gauze and PolyMem groups. Moreover, PUESi dressing showed better anti-adhesion properties and absorption capacity with deformation. Furthermore, the PUESi dressing shortened the inflammatory phase and enhanced collagen deposition in both the non-DM and DM animal models. To conclude, the PUESi dressing not only was fabricated with a simple and effective strategy but also enhanced wound healing via micronegative-pressure generation by its high absorption compacity with deformation.

StemRegenin-1 Attenuates Endothelial Progenitor Cell Senescence by Regulating the AhR Pathway-Mediated CYP1A1 and ROS Generation

Endothelial progenitor cell (EPC)-based stem cell therapy is a promising therapeutic strategy for vascular diseases. However, continuous in vitro expansion for clinical studies induces the loss of EPC functionality due to aging. In this study, we investigated the effects of StemRegenin-1 (SR-1), an antagonist of aryl hydrocarbon receptor (AhR), on replicative senescence in EPCs. We found that SR-1 maintained the expression of EPC surface markers, including stem cell markers, such as CD34, c-Kit, and CXCR4. Moreover, SR-1 long-term-treated EPCs preserved their characteristics. Subsequently, we demonstrated that SR-1 showed that aging phenotypes were reduced through senescence-associated phenotypes, such as β-galactosidase activity, SMP30, p21, p53, and senescence-associated secretory phenotype (SASP). SR-1 treatment also increased the proliferation, migration, and tube-forming capacity of senescent EPCs. SR-1 inhibited the AhR-mediated cytochrome P450 (CYP)1A1 expression, reactive-oxygen species (ROS) production, and DNA damage under oxidative stress conditions in EPCs. Furthermore, as a result of CYP1A1-induced ROS inhibition, it was found that accumulated intracellular ROS were decreased in senescent EPCs. Finally, an in vivo Matrigel plug assay demonstrated drastically enhanced blood vessel formation via SR-1-treated EPCs. In summary, our results suggest that SR-1 contributes to the protection of EPCs against cellular senescence.

Platelet-Derived Growth Factor-BB Priming Enhances Vasculogenic Capacity of Bone Marrow-Derived Endothelial Precursor Like Cells

BACKGROUND

Human endothelial progenitor cells (EPCs) were first identified in the peripheral blood and later in the cord blood and bone marrow (BM) with different vascularization capacity and different surface marker profiles. However, their identity and functional roles in neovascularization have not been clearly demonstrated in vivo and in vitro.

METHODS

Characterization of BM-EPC like cells were performed by fluorescence-activated cell sorting, immunofluorescence staining, enzyme-linked immunosorbent assay, Matrigel tube formation assay, and western blot analysis.

RESULTS

BM-EPC like cells were identified by selective adhesion to fibronectin and collagen from BM mononuclear cells, which generate fast-growing colonies with spindle morphology, express surface markers of CD105, vWF, UEA-I lectin binding, secrete HGF, VEGF, TGF-beta1 but can be distinguished from circulating EPC and endothelial cells by no expression of surface markers such as CD31, CD309, CD45, and CD34. These BM-EPC like cells shared many cell surface markers of BM-mesenchymal stem cells (MSC) but also can be distinguished by their vasculogenic property and other unique surface markers. Furthermore, the vasculogenic capacity of BM-EPC like cells were enhanced by co-culture of BM-MSC or PDGF-BB priming. PDGF-BB stimulated cell migration, proliferation, and secretion of laminin β-1, which was proposed as one of the mechanisms involved in the better vascularization of BM-EPC like cells.

CONCLUSION

PDGF-BB priming may be applied to improve the potency and function of BM-EPC like cells as vasculogenic cell therapy for the ischemic vascular repair.

Gap26 inhibited angiogenesis through the β-catenin-VE-cadherin-VEGFR2-Erk signaling pathway

PURPOSE

To investigate the effect of connexin 43 (Cx43) on corneal neovascularization and its regulation of VEGFR2 on vascular endothelial cells.

METHODS

In vivo, we used mouse corneal suture model to induce corneal neovascularization and discovered the function of gap26 in corneal neovascularization. In vitro, the effect of gap26 on HUVEC was observed by cell proliferation, tube formation and scratch experiments. WB and PCR detected the changes in angiogenic protein and mRNA expression. Knockdown of key mRNA in neovascularization using siRNA confirmed that Cx43 regulates neovascularization through the β-catenin-VE-cadherin-VEGFR2-Erk signaling pathway.

RESULTS

In vivo, gap26 can reduce mouse corneal neovascularization. In vitro, we show that Cx43 expression is increased in the presence of VEGFA stimulation, and when we use gap26 to inhibit Cx43 can reduce vascular endothelial cell proliferation, tube formation and migration. We found that the expression of pVEGFR2 and pErk increased in response to VEGFA, while they decreased after using gap26. And the expression of β-catenin and VE-cadherin decreased in response to VEGFA, while they increased after using gap26. Furthermore, we found that Cx43 regulates angiogenesis through the β-catenin-VE-cadherin-VEGFR2-Erk pathway.

CONCLUSIONS

Gap26 can downregulate VEGFR2 phosphorylation by stabilizing the expression of β-catenin and VE-cadherin on the cell membrane, thereby inhibiting VEGFA-induced HUVECs proliferation, migration and tube formation and inhibiting corneal neovascularization.

Mechanisms of diabetic foot ulceration: A review

Diabetic foot ulcers (DFUs) are associated with complex pathogenic factors and are considered a serious complication of diabetes. The potential mechanisms underlying DFUs have been increasingly investigated. Previous studies have focused on the three aspects of diabetic peripheral vascular disease, neuropathy, and wound infections. With advances in technology, researchers have been gradually conducting studies using immune cells, endothelial cells, keratinocytes, and fibroblasts, as they are involved in wound healing. It has been reported that the upregulation or downregulation of molecular signaling pathways is essential for the healing of DFUs. With a recent increase in the awareness of epigenetics, its regulatory role in wound healing has become a much sought-after trend in the treatment of DFUs. This review focuses on four aspects involved in the pathogenesis of DFUs: physiological and pathological mechanisms, cellular mechanisms, molecular signaling pathway mechanisms, and epigenetics. Given the challenge in the treatment of DFUs, we are hopeful that our review will provide new ideas for peers.

Correlation between stem cell molecular phenotype and atherosclerotic plaque neointima formation and analysis of stem cell signal pathways

Vascular stem cells exist in the three-layer structure of blood vessel walls and play an indispensable role in angiogenesis under physiological conditions and vascular remodeling under pathological conditions. Vascular stem cells are mostly quiescent, but can be activated in response to injury and participate in endothelial repair and neointima formation. Extensive studies have demonstrated the differentiation potential of stem/progenitor cells to repair endothelium and participate in neointima formation during vascular remodeling. The stem cell population has markers on the surface of the cells that can be used to identify this cell population. The main positive markers include Stem cell antigen-1 (Sca1), Sry-box transcription factor 10 (SOX10). Stromal cell antigen 1 (Stro-1) and Stem cell growth factor receptor kit (c-kit) are still controversial. Different parts of the vessel have different stem cell populations and multiple markers. In this review, we trace the role of vascular stem/progenitor cells in the progression of atherosclerosis and neointima formation, focusing on the expression of stem cell molecular markers that occur during neointima formation and vascular repair, as well as the molecular phenotypic changes that occur during differentiation of different stem cell types. To explore the correlation between stem cell molecular markers and atherosclerotic diseases and neointima formation, summarize the differential changes of molecular phenotype during the differentiation of stem cells into smooth muscle cells and endothelial cells, and further analyze the signaling pathways and molecular mechanisms of stem cells expressing different positive markers participating in intima formation and vascular repair. Summarizing the limitations of stem cells in the prevention and treatment of atherosclerotic diseases and the pressing issues that need to be addressed, we provide a feasible scheme for studying the signaling pathways of vascular stem cells involved in vascular diseases.

Advances in microRNA from adipose-derived mesenchymal stem cell-derived exosome: focusing on wound healing

Skin wounds are a common condition causing economic burden and they represent an urgent clinical need, especially chronic wounds. Numerous studies have been conducted on the applications of stem cell therapy in wound healing, with adipose-derived mesenchymal stem cells (ADMSCs) playing a major role since they can be isolated easily, yielding a high number of cells, the less invasive harvesting required, the longer life span and no ethical issues. However, the lack of standardized doses and protocols, the heterogeneity of clinical trials, as well as the incompatibility of the immune system limit its application. Recent studies have demonstrated that specific stem cell functions depend on paracrine factors, including extracellular vesicles, in which microRNAs in exosomes (Exo-miRNAs) are essential in controlling their functions. This paper describes the application and mechanism whereby ADMSC-Exo-miRNA regulates wound healing. ADMSC-Exo-miRNA is involved in various stages in wounds, including modulating the immune response and inflammation, accelerating skin cell proliferation and epithelialization, promoting vascular repair, and regulating collagen remodeling thereby reducing scar formation. In summary, this acellular therapy based on ADMSC-Exo-miRNA has considerable clinical potential, and provides reference values for developing new treatment strategies for wound healing.

Intraoperative Creation of Tissue-Engineered Grafts with Minimally Manipulated Cells: New Concept of Bone Tissue Engineering In Situ

Transfer of regenerative approaches into clinical practice is limited by strict legal regulation of in vitro expanded cells and risks associated with substantial manipulations. Isolation of cells for the enrichment of bone grafts directly in the Operating Room appears to be a promising solution for the translation of biomedical technologies into clinical practice. These intraoperative approaches could be generally characterized as a joint concept of tissue engineering in situ. Our review covers techniques of intraoperative cell isolation and seeding for the creation of tissue-engineered grafts in situ, that is, directly in the Operating Room. Up-to-date, the clinical use of tissue-engineered grafts created in vitro remains a highly inaccessible option. Fortunately, intraoperative tissue engineering in situ is already available for patients who need advanced treatment modalities.

Low Temperature Plasma Jet Affects Acute Skin Wounds in Diabetic Mice Through Reactive Components

As a common complication of diabetes, diabetic foot ulcers serious affect the life quality even lead to amputation if it's not properly treated. In this paper, we developed a Low Temperature Plasma Jet (LTPJ) system for treating diabetic foot ulcers on streptozotocin-induced diabetic mice. This system generates time-dependent reactive nitrogen and oxygen species (RNOS), which have temperature below 40°C. The wound area of normal mice was significantly reduced after LTPJ treatment. Histological and immunohistochemistry analysis showed faster deposition of collagen and more vessel formation both in plasma-treated normal and diabetic mice on Day 3. However, diabetic wounds showed poor collagen deposition and angiogenesis on Day 8, which might be the reason of slow wound healing. Reactive nitrogen species (RNS) that generated by LTPJ can promote endogenous nitric oxide (NO) production in diabetic wounds, thus promoting inflammation, stromal deposition, angiogenesis, cell proliferation and remodeling, while excess reactive oxygen species (ROS) will exacerbate oxidative stress in wound tissues of diabetic mice. In conclusion, LTPJ improved acute wound healing in normal mice, increased collagen deposition and angiogenesis in initial diabetic wound healing, but had no significant effect on diabetic wound healing rate.

Advances in neovascularization after diabetic ischemia

With the high incidence of diabetes around the world, ischemic complications cause a serious influence on people’s production and living. Neovascularization plays a significant role in its development. Therefore, neovascularization after diabetic ischemia has aroused attention and has become a hot spot in recent years. Neovascularization is divided into angiogenesis represented by atherosclerosis and arteriogenesis characterized by coronary collateral circulation. When mononuclear macrophages successively migrate to the ischemia anoxic zone after ischemia or hypoxia, they induce the secretion of cytokines, such as vascular endothelial growth factor and hypoxia-inducible factor, activate signaling pathways such as classic Wnt and phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) pathways, trigger oxidative stress response, activate endothelial progenitor cells or enter the glycolysis or lactic acid process and promote the formation of new blood vessels, remodeling them into mature blood vessels and restoring blood supply. However, the hypoglycemic condition has different impacts on neovascularization. Consequently, this review aimed to introduce the mechanisms of neovascularization after diabetic ischemia, increase our un-derstanding of diabetic ischemic complications and their therapies and provide more treatment options for clinical practice and effectively relieve patients’ pain. It is believed that in the near future, neovascularization will bring more benefits and hope to patients with diabetes.

Exosomal ncRNAs: The pivotal players in diabetic wound healing

Diabetes is the most prevalent metabolic disease in the world today. In addition to elevated blood glucose, it also causes serious complications, which has a significant effect on the quality of life of patients. Diabetic trauma is one of complications as a result of the interaction of diabetic neuropathy, peripheral vascular disease, infection, trauma, and other factors. Diabetic trauma usually leads to poor healing of the trauma and even to severe foot ulcers, wound gangrene, and even amputation, causing serious psychological, physical, and financial burdens to diabetic patients. Non-coding RNAs (ncRNAs) carried by exosomes have been demonstrated to be relevant to the development and treatment of diabetes and its complications. Exosomes act as vehicle, which contain nucleic acids such as mRNA and microRNA (miRNA), and play a role in the intercellular communication and the exchange of substances between cells. Because exosomes are derived from cells, there are several advantages over synthetic nanoparticle including good biocompatibility and low immunogenicity. Exosomal ncRNAs could serve as markers for the clinical diagnosis of diabetes and could also be employed to accelerate diabetic wound healing via the regulation of the immune response and modulation of cell function. ncRNAs in exosomes can be employed to promote diabetic wound healing by regulating inflammation and accelerating re-vascularization, re-epithelialization, and extracellular matrix remodeling. Herein, exosomes in terms of ncRNA (miRNA, lncRNA, and circRNA) to accelerate diabetic wounds healing were summarized, and we discussed the challenge of the loading strategy of ncRNA into exosomes.

Nanofibrous Vildagliptin/PLGA Membranes Accelerate Diabetic Wound Healing by Angiogenesis

The inhibition of dipeptidyl peptidase-4 (DPP4) significantly enhances the wound closure rate in diabetic patients with chronic foot ulcers. DPP4 inhibitors are only prescribed for enteral, but topical administration, if feasible, to a wound would have more encouraging outcomes. Nanofibrous drug-eluting poly-D-L-lactide-glycolide (PLGA) membranes that sustainably release a high concentration of vildagliptin were prepared to accelerate wound healing in diabetes. Solutions of vildagliptin and PLGA in hexafluoroisopropanol were electrospun into nanofibrous biodegradable membranes. The concentration of the drug released in vitro from the vildagliptin-eluting PLGA membranes was evaluated, and it was found that effective bioactivity of vildagliptin can be discharged from the nanofibrous vildagliptin-eluting membranes for 30 days. Additionally, the electrospun nanofibrous PLGA membranes modified by blending with vildagliptin had smaller fiber diameters (336.0 ± 69.1 nm vs. 743.6 ± 334.3 nm, p < 0.001) and pore areas (3405 ± 1437 nm2 vs. 8826 ± 4906 nm2, p < 0.001), as well as a higher hydrophilicity value (95.2 ± 2.2° vs. 113.9 ± 4.9°, p = 0.004), and showed a better water-retention ability within 24 h compared with PLGA membranes. The vildagliptin-eluting PLGA membrane also enhanced the diabetic wound closure rate for two weeks (11.4 ± 3.0 vs. 18.7 ± 2.6 %, p < 0.001) and the level of the angiogenesis using CD31 expression (1.73 ± 0.39 vs. 0.45 ± 0.17 p = 0.006 for Western blot; 2.2 ± 0.5 vs. 0.7 ± 0.1, p < 0.001 for immunofluorescence). These results demonstrate that nanofibrous drug-eluting PLGA membranes loaded with vildagliptin are an effective agent for sustained drug release and, therefore, for accelerating cutaneous wound healing in the management of diabetic wounds.

Elucidation of endothelial progenitor cell dysfunction in diabetes by RNA sequencing and constructing lncRNA-miRNA-mRNA competing endogenous RNA network

With the rapid increase in the incidence of diabetes, non-healing diabetic wounds have posed a huge challenge to public health. Endothelial progenitor cell (EPC) has been widely reported to promote wound repairing, while its number and function were suppressed in diabetes. However, the specific mechanisms and competing endogenous RNA (ceRNA) network of EPCs in diabetes remain largely unknown. Thus, the transcriptome analyses were carried in the present study to clarify the mechanism underlying EPCs dysfunction in diabetes. EPCs were successfully isolated from rats. Compared to the control, diabetic rat-derived EPCs displayed impaired proliferation, migration, and tube formation ability. The differentially expressed (DE) RNAs were successfully identified by RNA sequencing in the control and diabetic groups. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that DE mRNAs were significantly enriched in terms and pathways involved in the functions of EPCs and wound healing. Protein-protein interaction networks revealed critical DE mRNAs in the above groups. Moreover, the whole lncRNA-miRNA-mRNA ceRNA network was constructed, in which 9 lncRNAs, 9 mRNAs, and 5 miRNAs were further validated by quantitative real-time polymerase chain reaction. Rno-miR-10b-5p and Tgfb2 were identified as key regulators of EPCs dysfunction in diabetes. The present research provided novel insight into the underlying mechanism of EPCs dysfunction in diabetes and prompted potential targets to restore the impaired functions, thus accelerating diabetic wound healing. KEY MESSAGES: • Compared to the control, diabetic rat-derived EPCs displayed impaired proliferation, migration, and tube formation ability. • The DE RNAs were successfully identified by RNA sequencing in the control and diabetic groups and analyzed by DE, GO, and KEGG analysis. • PPI and lncRNA-miRNA-mRNA ceRNA networks were constructed. • 9 lncRNAs, 9 mRNAs, and 5 miRNAs were further validated by qRT-PCR. • Rno-miR-10b-5p and Tgfb2 were identified as key regulators of EPCs dysfunction in diabetes.

Adipose-Derived Stem Cells for the Treatment of Diabetic Wound: From Basic Study to Clinical Application

Diabetic wounds significantly affect the life quality of patients and may cause amputation and mortality if poorly managed. Recently, a wide range of cell-based methods has emerged as novel therapeutic methods in treating diabetic wounds. Adipose-derived stem cells (ASCs) are considered to have the potential for widespread clinical application of diabetic wounds treatment in the future. This review summarized the mechanisms of ASCs to promote diabetic wound healing, including the promotion of immunomodulation, neovascularization, and fibro synthesis. We also review the current progress and limitations of clinical studies using ASCs to intervene in diabetic wound healing. New methods of ASC delivery have been raised in recent years to provide a standardized and convenient use of ASCs.

A potential fate decision landscape of the TWEAK/Fn14 axis on stem and progenitor cells: a systematic review

Stem and progenitor cells (SPCs) possess self-remodeling ability and differentiation potential and are responsible for the regeneration and development of organs and tissue systems. However, the precise mechanisms underlying the regulation of SPC biology remain unclear. Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) acts on miscellaneous cells via binding to fibroblast growth factor-inducible 14 (Fn14) and exerts pleiotropic functions in the regulation of divergent stem cell fates. TWEAK/Fn14 signaling can regulate the proliferation, differentiation, and migration of multiple SPCs as well as tumorigenesis in certain contexts. Although TWEAK’s roles in modulating multiple SPCs are sparsely reported, the systemic effector functions of this multifaceted protein have not been fully elucidated. In this review, we summarized the fate decisions of TWEAK/Fn14 signaling on multiple stem cells and characterized its potential in stem cell therapy.

CircRNA-miRNA interactions in atherogenesis

Atherosclerosis is the major cause of coronary artery disease (CAD) which includes unstable angina, myocardial infarction, and heart failure. The onset of atherogenesis, a process of atherosclerotic lesion formation in the intima of arteries, is driven by lipid accumulation, a vicious cycle of reactive oxygen species (ROS)-induced oxidative stress and inflammatory reactions leading to endothelial cell (EC) dysfunction, vascular smooth muscle cell (VSMC) activation, and foam cell formation which further fuel plaque formation and destabilization. In recent years, there is a surge in the number of publications reporting the involvement of circular RNAs (circRNAs) in the pathogenesis of cardiovascular diseases, cancers, and metabolic syndromes. These studies have advanced our understanding on the biological functions of circRNAs. One of the most common mechanism of action of circRNAs reported is the sponging of microRNAs (miRNAs) by binding to the miRNAs response element (MRE), thereby indirectly increases the transcription of their target messenger RNAs (mRNAs). Individual networks of circRNA-miRNA-mRNA associated with atherogenesis have been extensively reported, however, there is a need to connect these findings for a complete overview. This review aims to provide an update on atherogenesis-related circRNAs and analyze the circRNA-miRNA-mRNA interactions in atherogenesis. The atherogenic mechanisms and clinical relevance of each atherogenesis-related circRNA were systematically discussed for better understanding of the knowledge gap in this area.

PBMNCs Treatment in Critical Limb Ischemia and Candidate Biomarkers of Efficacy

When in critical limb ischemia (CLI) the healing process aborts or does not follow an orderly and timely sequence, a chronic vascular wound develops. The latter is major problem today, as their epidemiology is continuously increasing due to the aging population and a growth in the incidence of the underlying diseases. In the US, the mean annualized prevalence of necrotic wounds due to the fact of CLI is 1.33% (95% CI, 1.32–1.34%), and the cost of dressings alone has been estimated at USD 5 billion per year from healthcare budgets. A promising cell treatment in wound healing is the local injection of peripheral blood mononuclear cells (PBMNCs). The treatment is aimed to induce angiogenesis as well to switch inflammatory macrophages, called the M1 phenotype, into anti-inflammatory macrophages, called M2, a phenotype devoted to tissue repair. This mechanism is called polarization and is a critical step for the healing of all human tissues. Regarding the clinical efficacy of PBMNCs, the level of evidence is still low, and a considerable effort is necessary for completing the translational process toward the patient bed site. From this point of view, it is crucial to identify some candidate biomarkers to detect the switching process from M1 to M2 in response to the cell treatment.

Effective high-throughput isolation of enriched platelets and circulating pro-angiogenic cells to accelerate skin-wound healing

Delayed wound healing and chronic skin lesions represent a major health problem. Over the past years, growth factors mediated by platelet-rich plasma (PRP) and cell-based therapies were developed as effective and affordable treatment able to improve wound healing capacity. We have advanced existing concepts to develop a highly efficient high-throughput protocol with proven application for the isolation of PRP and pro-angiogenic cells (Angio^PRP). This protocol outlines the effectiveness of Angio^PRP in promoting the critical healing process including wound closure, re-epithelialization, granulation tissue growth, and blood vessel regeneration. We coupled this effect with normalization of mechanical properties of rescued mouse wounds, which is sustained by a correct arrangement of elastin and collagen fibers. Proteomic analysis of treated wounds demonstrated a fingerprint of Angio^PRP based on the up-regulation of detoxification pathway of glutathione metabolism, correlated to a decrease in inflammatory response. Overall, these results have enabled us to provide a framework for how Angio^PRP supports wound healing, opening avenues for further clinical advances.

Bioactive extracellular matrix scaffolds engineered with proangiogenic proteoglycan mimetics and loaded with endothelial progenitor cells promote neovascularization and diabetic wound healing

Diabetic ischemic wound treatment remains a critical clinical challenge. Neovascularization plays a significant role in wound healing during all stages of the tissue repair process. Strategies that enhance angiogenesis and neovascularization and improve ischemic pathology may promote the healing of poor wounds, particularly diabetic wounds in highly ischemic conditions. We previously identified a cyclic peptide LXW7 that specifically binds to integrin αvβ3 on endothelial progenitor cells (EPCs) and endothelial cells (ECs), activates vascular endothelial growth factor (VEGF) receptors, and promotes EC growth and maturation. In this study, we designed and synthesized a multi-functional pro-angiogenic molecule by grafting LXW7 and collagen-binding peptides (SILY) to a dermatan sulfate (DS) glycosaminoglycan backbone, named LXW7-DS-SILY, and further employed this multi-functional molecule to functionalize collagen-based extracellular matrix (ECM) scaffolds. We confirmed that LXW7-DS-SILY modification significantly promoted EPC attachment and growth on the ECM scaffolds in vitro and supported EPC survival in vivo in the ischemic environment. When applied in an established Zucker Diabetic Fatty (ZDF) rat ischemic skin flap model, LXW7-DS-SILY-functionalized ECM scaffolds loaded with EPCs significantly improved wound healing, enhanced neovascularization and modulated collagen fibrillogenesis in the ischemic environment. Altogether, this study provides a promising novel treatment to accelerate diabetic ischemic wound healing, thereby reducing limb amputation and mortality of diabetic patients.

Phase I/IIa Feasibility Trial of Autologous Quality- and Quantity-Cultured Peripheral Blood Mononuclear Cell Therapy for Non-Healing Extremity Ulcers

Non-healing wounds are among the main causes of morbidity and mortality. We recently described a novel, serum-free ex vivo expansion system, the quantity and quality culture system (QQc), which uses peripheral blood mononuclear cells (PBMNCs) for effective and noninvasive regeneration of tissue and vasculature in murine and porcine models. In this prospective clinical study, we investigated the safety and efficacy of QQ-cultured peripheral blood mononuclear cell (MNC-QQ) therapy for chronic non-healing ischemic extremity wounds. Peripheral blood was collected from 9 patients with 10 chronic (>1 month) non-healing wounds (8 males, 1 female; 64-74 years) corresponding to ischemic extremity ulcers. PBMNCs were isolated and cultured using QQc. Within a 20-cm area surrounding the ulcer, 2 × 107 cells were injected under local anesthesia. Wound healing was monitored photometrically every 2 weeks. The primary endpoint was safety, whereas the secondary endpoint was efficacy at 12-week post-injection. All patients remained ambulant, and no deaths, other serious adverse events, or major amputations were observed for 12 weeks after cell transplantation. Six of the 10 cases showed complete wound closure with an average wound closure rate of 73.2% ± 40.1% at 12 weeks. MNC-QQ therapy increased vascular perfusion, skin perfusion pressure, and decreased pain intensity in all patients. These results indicate the feasibility and safety of MNC-QQ therapy in patients with chronic non-healing ischemic extremity wounds. As the therapy involves transplanting highly vasculogenic cells obtained from a small blood sample, it may be an effective and highly vasculogenic strategy for limb salvage.

EPC-EXs improve astrocyte survival and oxidative stress through different uptaking pathways in diabetic hypoxia condition

Background

Hyperglycemia contributes to cardiovascular complications in patients with type 2 diabetes. We confirmed that high glucose (HG) induces endothelial dysfunction and cerebral ischemic injury is enlarged in diabetic mice. Stem cell-released exosomes have been shown to protect the brain from ischemic stroke. We have previously shown that endothelial progenitor cells (EPCs)-released exosomes (EPC-EXs) can protect endothelial cells from hypoxia/reoxygenation (H/R) and HG-induced injury. Here, we aim to investigate the effects of EPC-EXs on astrocytes under H/R and HG-induced injury and whether miR-126 enriched EPC-EXs (miR126-EPC-EXs) have enhanced efficacy.

Methods

EPC-EX uptake and co-localization were measured by fluorescent microscopy using PKH26 and DAPI staining. miR-126 enrichment was achieved by transfecting with miR-126 mimics and quantified with real-time PCR. After co-incubation, cell death or injury was measured by using LDH (Lactate Dehydrogenase) assay. Oxidative stress/ROS (reactive oxygen species) generation was measured by DHE (Dihydroethidium) staining and lipid peroxidation assay.

Results

The EPC-EXs were effectively taken up by the astrocytes in a concentration as well as time-dependent manners and were co-localized within the nucleus as well as the cytoplasm. Pathway uptake inhibitors revealed that the EPC-EXs are effectively taken up by the clathrin-mediated, caveolin-dependent, and micropinocytosis via PI3K/Akt pathway. H/R and HG-induced a cell injury which could be protected by EPC-EXs evidenced by decreased cell cytotoxicity, oxidative stress, and lipid peroxidation. Moreover, miR-126 overexpression could increase the level of miR-126 in astrocytes and enhance the protective effects of EPC-EXs.

Conclusions

These results collectively indicate that the EPC-EXs could protect astrocytes against the HG plus H/R-induced damage.

Gene set enrichment analysis and ingenuity pathway analysis to identify biomarkers in Sheng-ji Hua-yu formula treated diabetic ulcers

ETHNOPHARMACOLOGICAL RELEVANCE

Sheng-ji Hua-yu (SJHY) formula is a Chinese herbal prescription for diabetic ulcers (DUs) treatment, which can accelerate wound reconstruction and shorten the healing time. However, its mechanism role maintains unclear.

AIM OF THE STUDY

To elucidate the molecular mechanisms of SJHY application on DUs.

MATERIALS AND METHODS

To begin with, transcriptome sequencing was adopted to identified differentially expression mRNAs among normal ulcers, DUs, and DUs + SJHY treatment in vivo. Liquid chromatography-tandem mass spectrometry was applied for the quality control of SJHY formula. GO and KEGG enrichment analysis were used to identify the mechanisms underlying the therapeutic effect of SJHY formula, and then gene set enrichment analysis and ingenuity pathway analysis were conducted for functional analysis. Further, qPCR detection was performed in vivo for validation.

RESULTS

SJHY administration could regulate the glucose metabolic process, AMPK and HIF-1 pathway to accelerate healing processes of DUs. Besides, CRHR1, SHH, and GAL were identified as the critical targets, and SLC6A3, GRP, FGF23, and CYP27B1 were considered as the upstream genes of SJHY treatment. Combined with animal experiments, the prediction results were validated in DUs mice model.

CONCLUSIONS

This study used modular pharmacology analysis to identify the biomarkers of SJHY formula and provide the potential therapeutic targets for DUs treatment as well.

The effects of electrical stimulation on diabetic ulcers of foot and lower limb: A systematic review

Diabetic foot ulcer (DFU) is a life-threatening condition affecting a third of diabetic patients. Many adjuvant therapies aimed at improving the healing rate (HR) and accelerating healing time are currently under investigation. Electrical stimulation (ES) is a physical-based therapy able to increase cells activity and migration into wound bed as well as inhibiting bacterial activity. The aim of this paper was to collect and analyse findings on the effects of ES used in combination with standard wound care (SWC) in the treatment of diabetic foot ulceration compared with SWC alone. A systematic review was performed to synthesise data from quantitative studies from eight databases. Article quality was assessed using the Crowe critical appraisal tool. Seven articles out of 560 publications met the inclusion criteria. A meta-analysis was not performed due to the heterogeneity of the studies and the results were narratively synthetised. Findings showed that HR appears to be higher among diabetic ulcers treated with ES; however, the reliability of these findings is affected by the small sample sizes of the studies. Furthermore, four studies are considered as moderate or high risk of bias. The evidence to suggest the systematic usage of ES in the treatment of DFUs is still insufficient.

An Up-to-Date Review of Biomaterials Application in Wound Management

Whether they are caused by trauma, illness, or surgery, wounds may occur throughout anyone's life. Some injuries' complexity and healing difficulty pose important challenges in the medical field, demanding novel approaches in wound management. A highly researched possibility is applying biomaterials in various forms, ranging from thin protective films, foams, and hydrogels to scaffolds and textiles enriched with drugs and nanoparticles. The synergy of biocompatibility and cell proliferative effects of these materials is reflected in a more rapid wound healing rate and improved structural and functional properties of the newly grown tissue. This paper aims to present the biomaterial dressings and scaffolds suitable for wound management application, reviewing the most recent studies in the field.

Regulation of endothelial progenitor cell functions during hyperglycemia: new therapeutic targets in diabetic wound healing

Diabetes is primarily characterized by hyperglycemia, and its high incidence is often very costly to patients, their families, and national economies. Unsurprisingly, the number and function of endothelial progenitor cells (EPCs) decrease in patients resulting in diabetic wound non-healing. As precursors of endothelial cells (ECs), these cells were discovered in 1997 and found to play an essential role in wound healing. Their function, number, and role in wound healing has been widely investigated. Hitherto, a lot of complex molecular mechanisms have been discovered. In this review, we summarize the mechanisms of how hyperglycemia affects the function and number of EPCs and how the affected cells impact wound healing. We aim to provide a complete summary of the relationship between diabetic hyperglycosemia, EPCs, and wound healing, as well as a better comprehensive platform for subsequent related research.

The effects of oral Aloe vera on the efficacy of transplanted human endothelial cells and the expression of matrix metalloproteinases in diabetic wound healing

Background

Diabetic wounds are characterized by delayed healing and impaired angiogenesis. Aloe vera and human umbilical vein endothelial cells (HUVECs) are reported to facilitate wound healing, and the former also has hypoglycemic property. Matrix metalloproteinases are enzymes that play a role in diabetic wound pathogenesis.

Objective

To investigate whether oral Aloe vera can enhance the efficacy of HUVEC transplantation and inhibit the expression of matrix metalloproteinases in wound healing of diabetic mice.

Materials and methods

BALB/c nude mice were randomly assigned into five groups: normal control group, diabetic group (DM), DM transplanted with HUVECs, DM treated with oral Aloe vera, and DM treated with combined HUVECs and oral Aloe vera. Diabetes was induced by streptozotocin. Bilateral full-thickness excision cutaneous wounds were created. At days 7 and 14 post-wounding, the following parameters were determined: blood glucose, wound area, wound perfusion, capillary vascularity, re-epithelialization rate and tissue VEGF levels. Tissue expressions of MMP-2 and MMP-9 were compared between the DM mice and those treated with oral Aloe vera.

Results

Over days 7 and 14, Aloe vera exerted glucose-lowering effect in diabetic mice. Higher wound closure rate, blood flow and capillary vascularity, and lower MMP-2 and MMP-9 expressions were observed at both time points in DM treated with Aloe vera group compared with DM group (P < 0.05). Moreover, combined therapy of HUVECs and oral Aloe vera was more effective than Aloe vera or HUVECs alone in increasing VEGF levels, capillary vascularity and wound perfusion. Blood glucose levels were negatively correlated with angiogenesis (P = 0.000.

Conclusion

It is suggested that oral Aloe vera enhances the efficacy of HUVEC transplantation on diabetic wound angiogenesis, partly through improving glycemic control. Oral Aloe vera also promotes diabetic wound healing via inhibition of MMP-2 and MMP-9 expressions.

Effect of Taspine hydrochloride on the repair of rat skin wounds by regulating keratinocyte growth factor signal

To explore the regulation of keratinocyte growth factor (KGF) in the process of repairing rat skin wounds by taspine hydrochloride (TA/HCl), 45 male Sprague-Dawley (SD) rats were purchased and divided into an experimental group, a dimethyl sulfoxide (DMSO) control group, and a basic fibroblast growth factor (bFGF) control group, each with 15 only. A back trauma model was innovatively adopted to prevent rats from biting and contaminating. The wound healing time and healing rate of the rat, and the Hydroxyproline (Hyp) and KGF expressions were observed. Morphological changes of wound tissue and the number of capillaries were observed after hematoxylin-eosin (HE) staining. The results showed that wound healing rate of experimental group and bFGF group was significantly higher than that of DMSO group (P < 0.05) after 2–15 days, and wound healing time of experimental group was 18 days, which was significantly lower than that of the DMSO group (P < 0.05). Expression levels of Hyp and KGF in the granulation tissue of rats in the experimental group were much higher than those in the DMSO control group after trauma (P < 0.05). In early stage of wound tissue repair, the number of new capillaries formed in experimental group was significantly higher than that in DMSO control group (P < 0.05). In summary, this study innovatively focused on KGF. The mechanism of TA/HCL promoting rat skin wound healing was closely related to KGF.

CD146 mediates the anti-apoptotic role of Netrin-1 in endothelial progenitor cells under hypoxic conditions

Modulating the biological status of endothelial progenitor cells (EPCs), such as function and survival, is essential for therapeutic angiogenesis in ischemic vascular disease environments. This study aimed to explore the role and molecular mechanisms underlying Netrin-1 in the viability and angiogenic function of EPCs. EPCs were isolated from the bone barrow of adult C57/BL6 mice. The apoptosis and various functions of EPCs were analyzed in vitro by manipulating the expression of Netrin-1. The TUNEL assay was performed to detect apoptotic EPCs. Cell migration and tube formation assays were performed to detect EPC function. Trypan blue staining was performed to detect cell viability. Western blot analysis was performed to detect the protein expression levels of Netrin-1, CD146 and apoptotic factors. Quantitative PCR analysis was performed to detect the expression levels of Netrin-1 receptors. The results demonstrated that treatment with exogenous Netrin-1 promoted EPC migration and tube formation, whereas transfection with small interfering (si)RNA targeting Netrin-1 exhibited the opposite effects. Exogenous Netrin-1 protected EPCs from hypoxia-induced apoptosis, whereas the interruption of endogenous Netrin-1 enhancement under hypoxia by Netrin-1-siRNA exacerbated the apoptosis of EPCs. Furthermore, CD146, one of the immunoglobulin receptors activated by Netrin-1, was screened for in the present study. Results demonstrated that CD146 did not participate in Netrin-1-promoted EPC function, but mediated the anti-apoptotic effects of Netrin-1 in EPCs. In conclusion, Netrin-1 enhanced the angiogenic function of EPCs and alleviated hypoxia-induced apoptosis, which was mediated by CD146. This biological function of Netrin-1 may provide a potential therapeutic option to promote EPCs for the treatment of ischemic vascular diseases.

Circ-Klhl8 overexpression increased the therapeutic effect of EPCs in diabetic wound healing via the miR-212-3p/SIRT5 axis

Previous studies found that hypoxic pretreatment of endothelial progenitor cells (EPCs) prior to transplantation had a greater therapeutic effect than untreated EPCs in promoting diabetic wound healing. However, the exact mechanism is uncertain. Here, circRNA expression in EPCs after hypoxic treatment was investigated. High-throughput sequencing was used to assess abnormal expression by EPCs of circular RNAs (circRNAs) following hypoxic pretreatment. Additionally, an in vivo full-thickness skin defect mouse model was used to assess the effects of transplanted EPCs on diabetic wound closure. Subsequently, the regulatory mechanism and targets were studied. The results showed that circ-Klhl8 overexpression suppressed hyper glucose-induced endothelial cell damage by activating autophagy. MiR-212-3p and SIRT5 were identified as the downstream targets of circ-Klhl8. Circ-Klhl8 overexpression promoted skin wound healing by regulating SIRT5-mediated autophagy. In conclusion, the study found that circ-Klhl8 overexpression increased the EPC therapeutic effect in promoting diabetic wound healing by targeting the miR-212-3p/SIRT5 axis.

Pharmaceutical Activation of Nrf2 Accelerates Diabetic Wound Healing by Exosomes from Bone Marrow Mesenchymal Stem Cells

Background and Objectives

Despite advances in wound treatments, chronic diabetic wounds remain a significant medical challenge. Exosomes from mesenchymal stem cells (MSCs) and small molecule activators of nuclear factor erythroid 2–related factor 2 (Nrf2) have emerged as potential therapies for nonhealing diabetic wounds. This study aimed to evaluate the effects of exosomes from bone marrow-derived MSCs (BMSCs) alone, or in combination with a small molecule activator of Nrf2 on diabetic wound healing.

Methods and Results

BMSCs and endothelial progenitor cells (EPCs) were isolated from the femur and tibia bone marrow of Sprague-Dawley (SD) rats and culture-expanded. Exosomes were harvested from the BMSC culture supernatants through ultracentrifugation. The effects of the exosomes and Nrf2 knockdown, alone or in combination, on EPC tube formation were evaluated. Streptozotocin-induced diabetic rats bearing a fresh full-thickness round wound were treated with the exosomes alone, or in combination with a lentiviral shRNA targeting Nrf2 (Lenti-sh-Nrf2) or tert-butylhydroquinone (tBHQ), a small molecule activator of Nrf2. Two weeks later, wound closure, re-epithelization, collagen deposition, neovascularization, and local inflammation were evaluated. BMSC exosomes promoted while Nrf2 knockdown inhibited EPC tube formation. BMSC exosomes accelerated wound closure, re-epithelization, collagen deposition, and neovascularization, and reduced wound inflammation in diabetic rats. These regenerative and anti-inflammatory effects of the exosomes were inhibited by Lenti-sh-Nrf2 but enhanced by tBHQ administration.

Conclusions

BMSC exosomes in combination with a small molecule Nrf2 activator hold promise as a new therapeutic option for chronic diabetic wounds.

The emerging roles of neutrophil extracellular traps in wound healing

Delayed wound healing causes problems for many patients both physically and psychologically, contributing to pain, economic burden, loss of function, and even amputation. Although many factors affect the wound healing process, abnormally prolonged or augmented inflammation in the wound site is a common cause of poor wound healing. Excessive neutrophil extracellular trap (NET) formation during this phase may amplify inflammation and hinder wound healing. However, the roles of NETs in wound healing are still unclear. Herein, we briefly introduce NET formation and discuss the possible NET-related mechanisms in wound healing. We conclude with a discussion of current studies, focusing on the roles of NETs in diabetic and normoglycemic wounds and the effectiveness of NET-targeting treatments in wound healing.

Physical Exercise Protects Against Endothelial Dysfunction in Cardiovascular and Metabolic Diseases

Increasing evidence shows that endothelial cells play critical roles in maintaining vascular homeostasis, regulating vascular tone, inhibiting inflammatory response, suppressing lipid leakage, and preventing thrombosis. The damage or injury of endothelial cells induced by physical, chemical, and biological risk factors is a leading contributor to the development of mortal cardiovascular and cerebrovascular diseases. However, the underlying mechanism of endothelial injury remains to be elucidated. Notably, no drugs effectively targeting and mending injured vascular endothelial cells have been approved for clinical practice. There is an urgent need to understand pathways important for repairing injured vasculature that can be targeted with novel therapies. Exercise training-induced protection to endothelial injury has been well documented in clinical trials, and the underlying mechanism has been explored in animal models. This review mainly summarizes the protective effects of exercise on vascular endothelium and the recently identified potential therapeutic targets for endothelial dysfunction.

Caveolin1: its roles in normal and cancer stem cells

PURPOSE

Stem cells are characterized by the capability of self-renewal and multi-differentiation. Normal stem cells, which are important for tissue repair and tissue regeneration, can be divided into embryonic stem cells (ESCs) and somatic stem cells (SSCs) depending on their origin. As a subpopulation of cells within cancer, cancer stem cells (CSCs) are at the root of therapeutic resistance. Tumor-initiating cells (TICs) are necessary for tumor initiation. Caveolin1 (Cav1), a membrane protein located at the caveolae, participates in cell lipid transport, cell migration, cell proliferation, and cell signal transduction. The purpose of this review was to explore the relationship between Cav1 and stem cells.

RESULTS

In ESCs, Cav1 is beneficial for self-renewal, proliferation, and migration. In SSCs, Cav1 exhibits positive or/and negative effects on stem cell self-renewal, differentiation, proliferation, migration, and angiogenic capacity. Cav1 deficiency impairs normal stem cell-based tissue repair. In CSCs, Cav1 inhibits or/and promotes CSC self-renewal, differentiation, invasion, migration, tumorigenicity ability, and CSC formation. And suppressing Cav1 promotes chemo-sensitivity in CSCs and TICs.

CONCLUSION

Cav1 shows dual roles in stem cell biology. Targeting the Cav1-stem cell axis would be a new way for tissue repair and cancer drug resistance.