Research progress on the therapeutic application of extracellular vesicles in erectile dysfunction.

Erectile dysfunction (ED) is one of the most common male sexual dysfunctions and is related to many pathogenic factors. However, first-line treatment, represented by phosphodiesterase 5 inhibitors, is unable to maintain long-term efficacy. Extracellular vesicles (EVs) have recently attracted the attention of researchers in the fields of cardiovascular disease, neurologic disease, and regenerative medicine and may become a treatment for ED. This article reviews recent applications of EVs in the treatment of ED from the aspects of the source, the therapeutic mechanism, and the strategies to enhance therapeutic efficacy. These research advances lay the foundation for further research and provide references for in-depth understanding of the therapeutic mechanism and possible clinical application of EVs in ED.

Comparison of the therapeutic effects of human umbilical cord blood-derived mesenchymal stem cells and adipose-derived stem cells on erectile dysfunction in a rat model of bilateral cavernous nerve injury.

Background: Cavernous nerve injury (CNI) is the leading cause of erectile dysfunction (ED) after radical prostatectomy and pelvic fracture. Transplantation of human adipose-derived stem cells (ASCs) has been widely used to restore erectile function in CNI-ED rats and patients. Umbilical cord blood-derived MSCs (CBMSCs) are similarly low immunogenic but much primitive compared to ASCs and more promising in large-scale commercial applications due to the extensive establishment of cord blood banks. However, whether CBMSCs and ASCs have differential therapeutic efficacy on CNI-ED and the underlying mechanisms are still not clear. Materials and methods: A bilateral cavernous nerve injury (BCNI) rat model was established by crushing the bilateral cavernous nerves. After crushing, ASCs and CBMSCs were intracavernously injected immediately. Erectile function, Masson staining, and immunofluorescence analyses of penile tissues were assessed at 4 and 12 weeks. PKH-26-labeled ASCs or CBMSCs were intracavernously injected to determine the presence and differentiation of ASCs or CBMSCs in the penis 3 days after injection. In vitro experiments including intracellular ROS detection, mitochondrial membrane potential assay, EdU cell proliferation staining, cell apoptosis assay, and protein chip assay were conducted to explore the underlying mechanism of CBMSC treatment compared with ASC treatment. Results: CBMSC injection significantly restored erectile function, rescued the loss of cavernous corporal smooth muscles, and increased the ratio of smooth muscle to collagen. PKH-26-labeled CBMSCs or ASCs did not colocalize with endothelial cells or smooth muscle cells in the corpus cavernosum. Moreover, the conditioned medium (CM) of CBMSCs could significantly inhibit the oxidative stress and elevate the mitochondria membrane potential and proliferation of Schwann cells. Better therapeutic effects were observed in the CBMSC group than the ASC group both in vivo and in vitro. In addition, the content of neurotrophic factors and matrix metalloproteinases in CBMSC-CM, especially NT4, VEGF, MMP1, and MMP3 was significantly higher than that of ASC-CM. Conclusion: Intracavernous injection of CBMSCs exhibited a better erectile function restoration than that of ASCs in CNI-ED rats owing to richer secretory factors, which can promote nerve regeneration and reduce extracellular matrix deposition. CBMSC transplantation would be a promising therapeutic strategy for CNI-ED regeneration in the future.

Topical administration of the secretome derived from human amniotic epithelial cells ameliorates psoriasis-like skin lesions in mice.

BACKGROUND: Psoriasis is a chronic inflammatory skin disease. Tissue stem cells have exhibited a therapeutic effect on psoriatic mice. However, the therapeutic effect of topical administration of the secretome derived from tissue stem cells on psoriasis has not been reported. METHODS: The secretome from human amniotic epithelial cells (AEC-SC) and human umbilical cord mesenchymal stem cells (UMSC-SC) was topically administrated on the back of imiquimod-induced psoriasis-like mice. Subsequently, we observed the skin lesions and skin inflammation of psoriasis-like mice. Next, we further analyzed the paracrine factors in AEC-SC and UMSC-SC by protein chips. Lastly, the effect of the crucial paracrine factor was investigated by imiquimod-induced psoriasis-like mice. RESULTS: We found that AEC-SC had a better therapeutic effect on attenuating psoriasis-like skin lesions including skin scales, skin redness and skin thickness than UMSC-SC, and it had a better regulatory effect on keratinocyte hyperproliferation and altered differentiation. Thus, we focused on AEC-SC. Further study showed that AEC-SC reduced the infiltration of neutrophils and interleukin-17-producing T cells. Next, the analysis of AEC-SC with protein chip revealed that the levels of anti-inflammatory factor interleukin-1 receptor antagonist (IL-1ra) were much higher in AEC-SC compared to that in UMSC-SC. More importantly, the beneficial effect of AEC-SC on psoriasis-like skin lesions and skin inflammation of mice were significantly impaired when neutralizing with IL-1ra antibody, while the recombinant human IL-1ra showed a less protective effect than AEC-SC. CONCLUSIONS: The present study demonstrated that AEC-SC could efficiently ameliorate psoriasis-like skin lesions and skin inflammation and IL-1ra plays an essential role. Therefore, topical administration of AEC-SC may provide a novel strategy for treating psoriasis-like inflammatory skin diseases.

Derivation and propagation of spermatogonial stem cells from human pluripotent cells.

OBJECTIVES: This study is designed to generate and propagate human spermatogonial stem cells (SSCs) derived from human pluripotent stem cells (hPSCs). METHODS: hPSCs were differentiated into SSC-like cells (SSCLCs) by a three-step strategy. The biological characteristics of SSCLCs were detected by immunostaining with antibodies against SSC markers. The ability of self-renewal was measured by propagating for a long time and still maintaining SSCs morphological property. The differentiation potential of SSCLCs was determined by the generation of spermatocytes and haploid cells, which were identified by immunostaining and flow cytometry. The transcriptome analysis of SSCLCs was performed by RNA sequencing. The biological function of SSCLCs was assessed by xeno-transplantation into busulfan-treated mouse testes. RESULTS: SSCLCs were efficiently generated by a 3-step strategy. The SSCLCs displayed a grape-like morphology and expressed SSC markers. Moreover, SSCLCs could be propagated for approximately 4 months and still maintained their morphological properties. Furthermore, SSCLCs could differentiate into spermatocytes and haploid cells. In addition, SSCLCs displayed a similar gene expression pattern as human GPR125+ spermatogonia derived from human testicular tissues. And more, SSCLCs could survive and home at the base membrane of seminiferous tubules. CONCLUSION: SSCLCs were successfully derived from hPSCs and propagated for a long time. The SSCLCs resembled their counterpart human GPR125+ spermatogonia, as evidenced by the grape-like morphology, transcriptome, homing, and functional characteristics. Therefore, hPSC-derived SSCLCs may provide a reliable cell source for studying human SSCs biological properties, disease modeling, and drug toxicity screening.

Human umbilical cord multipotent mesenchymal stromal cells alleviate acute ischemia-reperfusion injury of spermatogenic cells via reducing inflammatory response and oxidative stress.

BACKGROUND: This study was designed to determine the effect of human umbilical cord multipotent mesenchymal stromal cells (hUC-MSC) on acute ischemia/reperfusion (I/R) injury of spermatogenic cells. METHOD: The testicular I/R rat model was established through 720° torsion for 1 h. hUC-MSC were intravenously injected 10 min before detorsion. Injury severity of spermatogenic cells was estimated by Johnsen's score. The proliferating of recipient spermatogonia was measured by the immunostaining of antibodies against Ki67, and all germ cells were detected with DDX4 antibody. And recipient spermatogenesis was assessed by staining spermatozoa with lectin PNA. The levels of inflammatory factors were measured by real-time PCR. And the Selectin-E expression, neutrophil infiltration in the testes was detected by immunostaining. Germ cells apoptosis was tested by TUNEL assay and western blot. Furthermore, the oxidative stress was tested by reactive oxidative species (ROS) levels. In vitro, the condition medium (CM) of hUC-MSC was used to culture human umbilical vein endothelial cells (HUVECs), so as to assess the paracrine effect of hUC-MSC on HUVECs. The protein chip was used to measure the relative concentration of the secretory proteins in the CM of hUC-MSC. RESULT: hUC-MSC greatly alleviated the testicular injury induced by testis I/R. The levels of proinflammatory factors were downregulated by hUC-MSC in vivo and in vitro. Neutrophil infiltration, ROS, and germ cell apoptosis in testicular tissues were greatly reduced in the group of hUC-MSC. Paracrine factors secreted by hUC-MSC including growth factors, cytokines, and anti-inflammatory cytokine were rich. CONCLUSION: This study demonstrated that intravenously injected hUC-MSC could protect the spermatogenic cells against I/R injury by reducing the inflammatory response, apoptosis, and acute oxidative injury. Paracrine mechanism of hUC-MSC may contribute to the protection of spermatogenic cells against I/R injury. Therefore, the present study provides a method for clinical treatment of attenuate I/R injury of spermatogenic cells.

Decreased immunomodulatory and secretory capability of aging human umbilical cord mesenchymal stem cells in vitro.

Mesenchymal stem cell therapy has drawn much attention as a promising therapeutic option for the treatment of different diseases. Due to insufficient cell population derived from freshly isolated tissues, in vitro propagation is required prior to clinical use. However, reduced cell viability of aging mesenchymal stem cell (MSCs) with repeated propagations has yet not be fully investigated, especially for the biological characteristics of immunoregulatory ability and paracrine factors. In this study, we compared the biological properties of human umbilical cord-MSCs (hUC-MSCs) at different passages, especially for immunomodulatory ability and secretions. Our results showed that hUC-MSCs at early passage (P2) and late passage (P8) exhibited similar morphology and surface marker expression, but hUC-MSCs at P8 displayed reduced proliferation and differentiation potential, immunoregulatory and secretory ability. In particular, hUC-MSCs at P2 and P5 could significantly suppress the population of proinflammatory Th1 and Th17 cell subsets and upregulate Treg cells, but not with hUC-MSCs at P8. For paracrine mechanism, higher level of secretions such as growth factors, cell adhesions, anti-inflammatory factors of hUC-MSCs were observed at P2 and P5 compared to that at P8. Therefore, it is essential to verify and validate the biological characteristics of hUC-MSCs that possess a good vitality before they are released for clinical use. Altogether, this study provides a rationale and two important parameters for how to select appropriate passage and vitality of MSCs for cell therapy.