Efficacy of adipose-derived mesenchymal stem cell therapy in the treatment of chronic micro- and macrovascular complications of diabetes

Diabetes mellitus is a highly prevalent disease characterized by hyperglycaemia that damages the vascular system, leading to micro- (retinopathy, neuropathy, nephropathy) and macrovascular diseases (cardiovascular disease). There are also secondary complications of diabetes (cardiomyopathy, erectile dysfunction or diabetic foot ulcers). Stem cell-based therapies have become a promising tool targeting diabetes symptoms and its chronic complications. Among all stem cells, adipose-derived mesenchymal stem cells (ADMSCs) are of great importance because of their abundance, non-invasive isolation and no ethical limitations. Characteristics that make ADMSCs good candidates for cell-based therapy are their wide immunomodulatory properties and paracrine activities through the secretion of an array of growth factors, chemokines, cytokines, angiogenic factors and anti-apoptotic molecules. Besides, after transplantation, ADMSCs show great ex vivo expansion capacity and differentiation to other cell types, including insulin-producing cells, cardiomyocytes, chondrocytes, hepatocyte-like cells, neurons, endothelial cells, photoreceptor-like cells, or astrocytes. Preclinical studies have shown that ADMSC-based therapy effectively improved visual acuity, ameliorated polyneuropathy and foot ulceration, arrested the development and progression of diabetic kidney disease, or alleviated the diabetes-induced cardiomyocyte hypertrophy. However, despite the positive results obtained in animal models, there are still several challenges that need to be overcome before the results of preclinical studies can be translated into clinical applications. To date, there are several clinical trials or ongoing trials using ADMSCs in the treatment of diabetic complications, most of them in the treatment of diabetic foot ulcers. This narrative review summarizes the most recent outcomes on the usage of ADMSCs in the treatment of long-term complications of diabetes in both animal models and clinical trials.

Identification of hub biomarkers and exploring the roles of immunity, M6A, ferroptosis, or cuproptosis in rats with diabetic erectile dysfunction

BACKGROUND

Currently, patients with diabetic erectile dysfunction (DMED) were not satisfied with the effects of first-line phosphodiesterase type 5 inhibitors (PDE5Is). Hence, this paper was designed to mine hub biomarkers in DMED and explore its potential mechanisms.

METHODS

Gene expression matrix of DMED was downloaded from the gene expression omnibus (GEO; GSE2457) dataset. The top 20 genes were selected based on the connectivity degrees in protein-protein interaction (PPI) network. Functional enrichment analysis was utilized to reveal DMED-related signaling pathways. We also explored the roles of immunity, m6A, ferroptosis, or cuproptosis in DMED and constructed Sprague Dawley (SD) rats DMED model to verify gene expressions by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Based on the threshold, a total of 122 differently expressed genes (DEGs) were identified in DMED, including 39 up-regulated and 83 down-regulated genes. Functional enrichment analysis implied that these DEGs were significantly enriched in peroxisome proliferator-activated receptors, ferroptosis, hypoxia-inducible factor 1 signaling pathways, and so on. SD rats DMED model was also successfully established by us and validated by intracavernous pressure/mean arterial pressure, Masson's trichrome staining, and immunohistochemical analysis. We further verified the expression of these top 20 genes from the PPI network by qRT-PCR in the SD rats DMED model and finally identified Sparc, Lox, Srebf1, and Mmp3 as hub biomarkers (all p < 0.05). As for immunity and cuproptosis, our analysis indicated that DMED had nothing to do with them (all p > 0.05). Actually, DMED was markedly associated with m6A regulators and ferroptosis.

CONCLUSIONS

We identified Sparc, Lox, Srebf1, and Mmp3 as potential hub biomarkers in the SD rats DMED model for future drug development and found its significant associations with m6A regulators and ferroptosis, but not with immunity or cuproptosis.

Bibliometric and visualization analysis of literature relating to diabetic erectile dysfunction

INTRODUCTION

Diabetic erectile dysfunction (DMED) refers to erectile dysfunction secondary to diabetes. Erectile dysfunction is characterized by a persistent inability to achieve and maintain an erection sufficient to permit satisfactory sexual activity.

METHODS

Based on the Web of Science core collection database, we firstly analyzed the quantity and quality of publications in the field of DMED, secondly profiled the publishing groups in terms of country, institution, author's publication and cooperation network, and finally sorted out and summarized the hot topics of research.

RESULTS

From 2001 to 2022, a total of 1,403 articles relating to this topic were published in 359 journals. They represent the global research status, potential hotspots, and future research directions. The number of DMED-related publications and citations has steadily increased over the few past decades. Academic institutions from Europe and the United States have played a leading role in DMED research. The country, institution, journal, and author with the most publications were the United States (294), INHA University (39), the Journal of Sexual Medicine (156), and Ryu, Ji-Kan (29), respectively. The most common keywords were erectile dysfunction (796), men (256), diabetes (254), diabetes mellitus (239), prevalence (180), corpus cavernosum (171), dysfunction (155), mellitus (154), nitric-oxide synthase (153), and expression (140). The main keyword-based research topics and hotspots in the DMED field were oral sildenafil, smooth muscle relaxation, nitric oxide synthase, gene therapy, metabolic syndrome, cavernous nerve injury, stem cell, and penile prosthesis.

DISCUSSION

The terms oral sildenafil, smooth muscle relaxation, nitric oxide synthase, gene therapy, metabolic syndrome, cavernous nerve injury, stem cell, and penile prosthesis will be at the forefront of DMED-related research.

JAK2 deficiency improves erectile function in diabetic mice through attenuation of oxidative stress, apoptosis, and fibrosis

Background

Janus kinase 2 (JAK2) is activated in diabetic mellitus (DM) conditions and may enhance oxidative stress, apoptosis and fibrosis in many tissues. Whether JAK2 activation is involved in the occurrence of diabetic erectile dysfunction (ED) is unknown.

Objectives

We performed this study to investigate the effect of JAK2 deficiency on diabetic ED.

Materials and methods

Conditional JAK2 gene knockout mice (Cre^+/+‐JAK2^fl/fl) were used, in which JAK2 gene knockout could be induced by tamoxifen. Mice fell into four groups: control, JAK2 knockout (JAK2^−/−), DM, and DM with JAK2^−/−. DM was induced by intraperitoneal injection of streptozotocin. Two months later, JAK2 gene knockout was induced with tamoxifen in Cre^+/+‐JAK2^fl/fl mice. After another 2 months, erectile function was measured by electrical stimulation of the cavernous nerve, and penile tissues were harvested. Ratio of maximal intracavernosal pressure (MIP) to mean arterial blood pressure (MAP), expression and phosphorylation of JAK2, oxidative stress level, NO/Cyclic Guanosine Monophosphate (cGMP) pathway, apoptosis, fibrosis, and transforming growth factor beta 1 (TGF‐β1)/Smad/Collagen IV pathway in corpus cavernosum, were measured.

Results

JAK2 expression was remarkably decreased after induction with tamoxifen. JAK2 was activated in penile tissues of diabetic mice, and JAK2 deficiency could improve the impaired erectile function caused by DM. However, in mice without DM, JAK2 deficiency had no apparent influence on erectile function. Levels of oxidative stress, apoptosis, fibrosis, and TGF‐β1/Smad/Collagen IV pathway were all elevated by DM, whereas JAK2 deficiency lessened these alterations in diabetic mice. Moreover, JAK2 deficiency improved the expression of the down‐regulated NO/cGMP pathway in diabetic mice. In non‐diabetic mice, no apparent changes were found in aforementioned parameters after JAK2 gene knockout.

Discussion and conclusion

Our study showed that JAK2 deficiency could improve erectile function in diabetic mice, which might be mediated by reduction in oxidative stress, apoptosis, and fibrosis in corpus cavernosum.

How Does Diabetes Impair Penile Tissues during Erectile Dysfunction?

BACKGROUND

Erectile dysfunction (ED) is a significant but underestimated complication during diabetes mellitus (DM). Currently, few special treatments are available clinically due to the lack of specific therapeutic targets. Genomic analysis can be helpful to find potential targets. In this study, the gene expression under diabetic ED condition was analyzed using a gene array, and the significance of the outcomes was evaluated through clinical data.

METHODS

The expressions of 15923 genes were analyzed using R software. Differential expression genes (DEGs) were identified through the constructed volcano plot. The function enrichment of Gene Ontology (GO) and KEGG was screened with the DAVID online tool. The interaction between these DEGs was revealed through constructing a protein-protein interaction network and the hub genes were uncovered using the STRING and Cytoscape tool. Lastly, the data of diabetic ED patients were applied to verify the bioinformatics findings.

RESULTS

The study showed that 75 genes in the rat penile tissues were upregulated, while 97 genes were downregulated on the diabetic ED condition. These genes were mainly involved in extracellular matrix composition, collagen fibril organization, as well as protein digestion & absorption. Additionally, insulin-related signaling pathways were affected. The clinical analysis indicated that insulin resistance was associated with the diabetic ED severity. Notably, the bioinformatics analysis also suggested that ferroptosis pathway was probably activated under the diabetic ED condition.

CONCLUSION

The impaired protein synthesis induced by deficient insulin signaling is an important cause of the diabetic ED. The improvement of protein synthesis through restoring insulin function may be potentially useful for diabetic ED therapy.

Epigenetic silencing of microRNA-874-3p implicates in erectile dysfunction in diabetic rats by activating the Nupr1/Chop-mediated pathway

Diabetes is a global medical problem that causes many deaths every year. Complications caused by diabetes are serious and affect patients' quality of life. Diabetes mellitus erectile dysfunction (DMED) affects more than half of male diabetes patients. In this study, we determined the role of microRNA-874-3p (miR-874-3p) and nuclear protein-1 (Nupr1) in streptozocin-induced DMED rats. Control rats received equal amount of vehicle. These rats were also injected with lentiviral vector or agomir to silence or overexpress miR-874-3p or Nupr1. Apomorphine (100 μg/kg, s.c.) was used to induce erection and time of erection was recorded. Intracavernosal and mean arterial pressure ratio (ICP/MAP) were also recorded. O^2- level and concentration of thiobarbituric acid reactive substances (TBARs) were detected using lucigenin-derived chemiluminescence method and Colorimetry. Rat cavernosum tissues were collected for subsequent experiments. Cavernosum smooth muscle cells (CSMCs) were also used for in vitro experiments. Nupr1 was found highly expressed (by RT-qPCR and Western blot analysis) in cavernosum tissues from DMED rats. Nupr1 silencing improved the ICP/MAP ratio and erection time. Nupr1 silencing also reduced CSMC apoptosis (by TUNEL assay) as well as decreased O^2- level and TBAR concentration. Nupr1 was targeted and inhibited by miR-874-3p (by luciferase activity and RNA immunoprecipitation assays), which was downregulated in DMED. miR-874-3p downregulation was due to increased methylation at the promoter region (methylation-specific PCR). miR-874-3p overexpression improved erection time and reduced apoptosis. In summary, miR-874-3p was downregulated which led to increased apoptosis and erectile dysfunction in DMED rats, through inhibition of Nupr1-mediated pathway. This study may also provide a new therapeutic direction for the treatment of DMED.