The Influence of AGEs Environment on Proliferation, Apoptosis, Homeostasis, and Endothelial Cell Differentiation of Human Adipose Stem Cells

The role of programmed cell death in diabetic foot ulcers

Diabetic foot ulcer, is a chronic complication afflicting individuals with diabetes, continue to increase worldwide, immensely burdening society. Programmed cell death, which includes apoptosis, autophagy, ferroptosis, necroptosis and pyroptosis, has been increasingly implicated in the pathogenesis of diabetic foot ulcer. This review is based on an exhaustive examination of the literature on 'programmed cell death' and 'diabetic foot ulcers' via PubMed. The findings revealed that natural bioactive compounds, noncoding RNAs and certain proteins play crucial roles in the healing of diabetic foot ulcers through various forms of programmed cell death, including apoptosis, autophagy, ferroptosis and pyroptosis.

Effects of advanced glycation end products (AGEs) on the differentiation potential of primary stem cells: a systematic review

The formation and accumulation of advanced glycation end products (AGEs) have been associated with aging and the development, or worsening, of many degenerative diseases, such as atherosclerosis, chronic kidney disease, and diabetes. AGEs can accumulate in a variety of cells and tissues, and organs in the body, which in turn induces oxidative stress and inflammatory responses and adversely affects human health. In addition, under abnormal pathological conditions, AGEs create conditions that are not conducive to stem cell differentiation. Moreover, an accumulation of AGEs can affect the differentiation of stem cells. This, in turn, leads to impaired tissue repair and further aggravation of diabetic complications. Therefore, this systematic review clearly outlines the effects of AGEs on cell differentiation of various types of primary isolated stem cells and summarizes the possible regulatory mechanisms and interventions. Our study is expected to reveal the mechanism of tissue damage caused by the diabetic microenvironment from a cellular and molecular point of view and provide new ideas for treating complications caused by diabetes.

Combination therapy of hydrogel and stem cells for diabetic wound healing

Diabetic wounds (DWs) are a common complication of diabetes mellitus; DWs have a low cure rate and likely recurrence, thus affecting the quality of patients’ lives. As traditional therapy cannot effectively improve DW closure, DW has become a severe clinical medical problem worldwide. Unlike routine wound healing, DW is difficult to heal because of its chronically arrested inflammatory phase. Although mesenchymal stem cells and their secreted cytokines can alleviate oxidative stress and stimulate angiogenesis in wounds, thereby promoting wound healing, the biological activity of mesenchymal stem cells is compromised by direct injection, which hinders their therapeutic effect. Hydro-gels form a three-dimensional network that mimics the extracellular matrix, which can provide shelter for stem cells in the inflammatory microenvironment with reactive oxygen species in DW, and maintains the survival and viability of stem cells. This review summarizes the mechanisms and applications of stem cells and hydrogels in treating DW; additionally, it focuses on the different applications of therapy combining hydrogel and stem cells for DW treatment.

Potential of stem cells for treating infected Diabetic Foot Wounds and Ulcers: a systematic review

Infected diabetic foot ulcers (iDFUs) cause great concern, as they generally heal poorly and are precursive of diabetic-related foot amputation and even death. Scientists have tested various techniques in attempts to ascertain the best treatment for iDFUs; however, the results have remained inconclusive. Stem cell therapy (SCT) appears to improve iDFU through its antimicrobial impacts, yet cogent information regarding the repair of iDFUs with SCT is lacking. Herein, published articles are evaluated to report coherent information about the antimicrobial effects of SCT on the repair of iDFUs in diabetic animals and humans. In this systematic review, we searched the Scopus, Medline, Google Scholar, and Web of Science databases for relevant full-text English language articles published from 2000 to 2022 that described stem cell antimicrobial treatments, infected diabetic wounds, or ulcers. Ultimately, six preclinical and five clinical studies pertaining to the effectiveness of SCT on healing infected diabetic wounds or ulcers were selected. Some of the human studies confirmed that SCT is a promising therapy for diabetic wounds and ulcers. Notably, more controlled studies performed on animal models revealed that stem cells combined with a biostimulator such as photobiomodulation decreased colony forming units and hastened healing in infected diabetic wounds. Moreover, stem cells alone had lower therapeutic impact than when combined with a biostimulant.

Different therapeutic effects between diabetic and non-diabetic adipose stem cells in diabetic wound healing

OBJECTIVE

This study aimed to investigate how adipose tissue-derived stem cells (ASCs) from diabetic and from non-diabetic rats affect wound healing in different microenvironments.

METHOD

The two types of ASC-rich cells were distinguished by characteristic surface antigen detection. The ASC-rich cells were transplanted into the wounds of diabetic and non-diabetic rats. Wound healing rates were compared and the healing process in the wound margin sections was used to determine how ASC-rich cells affect wound healing in different microenvironments.

RESULTS

ASC density was decreased in diabetic rats. The generation time of ASC-rich cells from diabetic rats (d-ASC-rich cells) was longer than that of ASC-rich cells from non-diabetic rats. The number of pre-apoptotic cells in the third generation (passage 3) of d-ASC-rich cells was higher than that among the ASC-rich cells from non-diabetic rats. CD31 and CD34 expression was higher in d-ASC-rich cells than in ASC-rich cells from non-diabetic rats, whereas CD44 and CD105 expression was lower than that in ASC-rich cells from non-diabetic rats. Transplantation of ASC-rich cells from non-diabetic rats promoted wound healing in both non-diabetic and diabetic rats. In contrast, d-ASC-rich cells and enriched nuclear cells only promoted wound healing in non-diabetic rats. ASC-rich cell transplantation promoted greater tissue regeneration than d-ASC-rich cell transplantation.

CONCLUSION

ASC-rich cells promoted wound healing in diabetic and non-diabetic rats. ASC density was lower in the adipose tissue of diabetic rats compared with non-diabetic rats. d-ASC-rich cells did not promote wound healing in diabetic rats, suggesting that caution is warranted regarding the clinical use of diabetic adipose stem cell transplantation for the treatment of diabetic wounds.

Transplantation of photobiomodulation-preconditioned diabetic stem cells accelerates ischemic wound healing in diabetic rats

BACKGROUND

Diabetic foot ulcer is the most costly and complex challenge for patients with diabetes. We hereby assessed the effectiveness of different preconditioned adipose-derived mesenchymal stem cells (AD-MSCs) and photobiomodulation protocols on treating an infected ischemic wound in type 1 diabetic rats.

METHODS

There were five groups of rats: (1) control, (2) control AD-MSCs [diabetic AD-MSCs were transplanted (grafted) into the wound bed], (3) AD-MSC + photobiomodulation in vivo (diabetic AD-MSCs were grafted into the wound, followed by in vivo PBM treatment), (4) AD-MSCs + photobiomodulation in vitro, and (5) AD-MSCs + photobiomodulation in vitro + in vivo.

RESULTS

Diabetic AD-MSCs preconditioned with photobiomodulation had significantly risen cell function compared to diabetic AD-MSC. Groups 3 and 5 had significantly decreased microbial flora correlated to groups 1 and 2 (all, p = 0.000). Groups 2, 3, 4, and 5 had significantly improved wound closure rate (0.4, 0.4, 0.4, and 0.8, respectively) compared to group 1 (0.2). Groups 2-5 had significantly increased wound strength compared to group 1 (all p = 0.000). In most cases, group 5 had significantly better results than groups 2, 3, and 4.

CONCLUSIONS

Preconditioning diabetic AD-MSCs with photobiomodulation in vitro plus photobiomodulation in vivo significantly hastened healing in the diabetic rat model of an ischemic infected delayed healing wound.

Adipose-Derived Mesenchymal Stem Cells in the Treatment of Diabetic Foot Ulcers: A Review of Preclinical and Clinical Studies

This review provides an outline of the use of adipose-derived mesenchymal stem cells (AMSCs) in the treatment of diabetic foot ulcers (DFUs). A systematic search of PubMed and the Cochrane database was performed on October 2, 2019. Eighteen studies were identified (14 preclinical and 4 clinical). Studies in animal models have demonstrated that AMSCs enhance diabetic wound healing, accelerate granulation tissue formation, and increase reepithelialization and neovascularization. Only 1 randomized control trial has been published so far. Patients (n = 25) with DFUs were treated using an allogeneic AMSC directly on the wound bed as a primary dressing, and improvements were found in complete wound closure in the treatment group (n = 16). Three clinical studies showed that autologous AMSC might be a safe alternative to achieve therapeutic angiogenesis in patients with diabetes and peripheral arterial disease. Based on the available evidence, AMSCs hold promise in the treatment of DFUs. However, this evidence requires confirmation by well-designed trials. Additional studies are also required to understand some issues regarding this treatment for DFUs. For example, the potential application of autologous or allogeneic AMSCs in different types of DFUs, optimal dose/infusion schedules, safety evaluations, and cost-effectiveness.

Critical roles of PI3K/Akt/NF‑κB survival axis in angiotensin II‑induced podocyte injury

Numerous studies have reported that angiotensin (Ang) II, nephrin, and podocin serve pivotal roles in podocyte injury, and thus can lead to the occurrence of proteinuria and the progression of kidney diseases. This study aimed to investigate the effects of Ang II on the production of nephrin and podocin, and their relationship with podocyte injury. We also aimed to determine whether nephrin, podocin and caspase-9 production depends on the PI3K/Akt/nuclear factor (NF)-κB signaling pathway in cultured mouse podocytes. We treated mouse podocytes with different doses of Ang II (10⁻⁹, 10⁻⁸, 10⁻⁷ and 10⁻⁶ mol/l) for 12, 24, and 48 h to analyse cell viability, and at 10⁻⁶ mol/l Ang II for 12, 24, and 48 h to evaluate cell apoptosis. Cells were treated with 10⁻⁶ mol/l of Ang II and/or LY294002 (inhibitor of Akt) or 740Y-P (activator of PI3K) for 48 h to detect Akt, phosphorylated (phospho)-Akt, p65 NF-κB, and phospho-p65 NF-κB, nephrin, podocin and caspase-9 expression, and podocyte apoptosis. Treatment with Ang II suppressed the viability and promoted the apoptosis of podocytes in a dose- and time-dependent manner. Ang II decreased phospho-Akt, phospho-p65 NF-κB, nephrin, and podocin and increased caspase-9 expression, while podocyte apoptosis was promoted. LY294002 further enhanced Ang II-induced downregulation of Akt and p65 NF-κB activation, as well as upregulation of caspase-9 mRNA and protein, and promoted the apoptosis of podocytes. Of note, 740Y-P restored Ang II-induced downregulation of Akt and p65 NF-κB activation, and upregulation of caspase-9, and decreased podocyte apoptosis. Interestingly, LY294002 and 740Y-P were determined to have no notable effects on the expression of nephrin and podocin. The data suggested that Ang II could regulate the expression of nephrin, podocin and caspase-9. Collectively, our findings suggested that the PI3K/Akt/NF-κB survival axis may serve a pivotal role in podocyte injury.

Nanotechnology and multipotent adult progenitor cells in Reparative Medicine: therapeutic perspectives

The biology of stem cells is one of the most dynamic and promising fields of the biological sciences, since it is the basis for the development of organisms. Its biological complexity demands efforts from several lines of research aimed mainly at its therapeutic use. Nanotechnology has been emerging as a new field of study, which shows great potential in the treatment of various diseases. This new area of health has been called “Nanomedicine” or “Bionanotechnology”, which can be applied in Medicine by transport and drug delivery systems, robotic tools to be used in diagnostic and surgical processes, nanobiomaterials, gene therapies, nanobiomedical devices, among others. Because stem cells and Nanotechnology are two areas of extremely promising science, a new field of study, called “stem cell Nanotechnology”, has gradually emerged. In this, Nanotechnology is used to help the stem cells apply their therapeutic potential in the treatment, cure, and repair of the damaged tissues, in an effective and safe way. In this way, stem cell Nanotechnology has generated great interest, since it may result in significant contributions to Regenerative Medicine and tissue engineering. The present work aims to present the state-of-the-art regarding its therapeutic use in Human Medicine.

A review: therapeutic potential of adipose-derived stem cells in cutaneous wound healing and regeneration

As the most important barrier for the human body, the skin often suffers from acute and chronic injuries, especially refractory wounds, which seriously affect the quality of life of patients. For these refractory wounds that cannot be cured by various surgical methods, stem cell transplantation becomes an effective research direction. As one of the adult stem cells, adipose-derived stem cells play an indispensable role in the repair of skin wounds more than other stem cells because of their advantages such as immune compatibility and freedom from ethical constraints. Here, we actively explore the role of adipose-derived stem cells in the repair of cutaneous wound and conclude that it can significantly promote cutaneous wound healing and regeneration. Based on a large number of animal and clinical trials, we believe that adipose-derived stem cells will have a greater breakthrough in the field of skin wound repair in the future, especially in chronic refractory wounds.

Growth and function of equine endothelial colony forming cells labeled with semiconductor quantum dots

BACKGROUND

Endothelial progenitor cells (EPCs) contribute to neovascularization and vascular repair in vivo and are attractive for clinical use in ischemic disease. Tracking of stem and progenitor cells is essential to determine engraftment after administration. Semiconductor quantum dots (QD) are promising for cell labeling due to their ease of uptake by many cell lines and their continued presence after many cell generations. The purpose of this study was to evaluate function and growth of equine EPCs after QD labeling. Additionally, this study evaluated the duration of QD label retention and mechanisms of QD label loss.

RESULTS

Endothelial colony forming cells (ECFCs) from adult horses (N = 3) were employed for this study, with QD labeled and unlabeled ECFCs tested from each horse. Cell proliferation of ECFCs labeled with QD at 20 nM was quantified by comparing the number of cell doublings per day (NCD) and the population doubling time (PDT) in labeled and unlabeled cells. Function of labeled and unlabeled ECFCs was assessed by comparing uptake of acetylated low-density lipoprotein (DiO-Ac-LDL) and tubule formation on growth factor containing matrix. Cell proliferation was not impacted by QD labeling; both NCD (p = 0. 95) and PDT (P = 0. 91) did not differ between unlabeled and QD labeled cells. Function of ECFCs assessed by DiO-Ac-LDL and tubule formation was also not different between unlabeled and QD labeled cells (P = 0. 33 and P = 0. 52, respectively). ECFCs retained their QD labeling over 7 passages with both 5 nM and 20 nM label concentrations. Reduction in label intensity was observed over time, and the mechanism was determined to be cell division.

CONCLUSIONS

Equine ECFCs are effectively labeled with QD, and QD concentrations up to 20 nM do not affect cell growth or function. QD label loss is a result of cell division. The use of QD labeling with equine EPCs may be an ideal way to track engraftment of EPCs for in vivo applications.