The aim of this study was to determine the possibility of improving erectile dysfunction using cell therapy with either human urine-derived stem cells (USCs) or USCs genetically-modified with FGF2 in a type 2 diabetic rat model. Human USCs were collected from 3 healthy donors. USCs were transfected with FGF2 (USCs-FGF2). Sixty-five SD male rats were divided into five groups (G). A control group of normal rats (G1, n = 10), and four other test groups of type 2 diabetic erectile dysfunction rats: PBS as a negative control (G2, n = 10), USCs (G3, n = 15), lentivirus-FGF2 (G4, n = 15), and USCs-FGF2 (G5, n = 15). Diabetes was induced in the rats via a high fat diet for 28 days and a subsequent intraperitoneal injection of streptozotocin (35 mg/kg). Erectile dysfunction was screened with apomorphine (100 μg/kg). Cell injections in the test groups (G2–G5) occurred directly into the corpora cavernosa. The implanted cells were tracked at 7 days (n = 5 animals/G) and 28 days (n = 10 animals/G) post injection. Mean arterial pressure (MAP), intracavernosal pressure (ICP), expression of endothelial markers (CD31, VEGF and eNOS), smooth muscle markers (desmin and smoothelin), histological changes and erectile function were assessed for each group. USCs expressed mesenchymal stem cell markers, and secreted a number of proangiogenic growth factors. USCs expressed endothelial cell markers (CD31 and vWF) after transfection with FGF2. Implanted USCs or USCs-FGF2 displayed a significantly raised ICP and ICP/MAP ratio (p<0.01) 28 days after intracavernous injection. Although few cell were detected within the implanted sites, histological and western blot analysis demonstrated an increased expression of endothelial and smooth muscle markers within the cavernous tissue following USC or USC-FGF2 injection. The paracrine effect of USCs or USCs-FGF2 induced improvement of erectile function in type 2 diabetic rats by recruiting resident cells and increasing the endothelial expression and contents of smooth muscle.

The aim of this study was to determine whether adipose derived stem cells (ADSCs) expressing vascular endothelial growth factor (VEGF) gene can improve endothelial function, recover the impaired VEGF signaling pathway and enhance smooth muscle contents in a rat diabetic erectile dysfunction (DED) model. DED rats were induced via intraperitoneal injection of streptozotocin (40 mg/kg), and then screened by apomorphine (100 µg/kg). Five groups were used (n = 12/group)–Group 1 (G1): intracavernous injection of lentivirus-VEGF; G2: ADSCs injection; G3: VEGF-expressing ADSCs injection; G4: Phosphate buffered saline injection; G1–G4 were DED rats; G5: normal rats. The mean arterial pressure (MAP) and intracavernosal pressure (ICP) were measured at days 7 and 28 after the injections. The components of the VEGF system, endothelial, smooth muscle, pericytes markers in cavernoursal tissue were assessed. On day 28 after injection, the group with intracavernosum injection of ADSCs expressing VEGF displayed more efficiently and significantly raised ICP and ICP/MAP (p<0.01) than those with ADSCs or lentivirus-VEGF injection. Western blot and immunofluorescent analysis demonstrated that improved erectile function by ADSCs-VEGF was associated with increased expression of endothelial markers (VEGF, VEGF R1, VEGF R2, eNOS, CD31 and vWF), smooth muscle markers (a-actin and smoothelin), and pericyte markers (CD146 and NG2). ADSCs expressing VEGF produced a therapeutic effect and restored erectile function in diabetic rats by enhancing VEGF-stimulated endothelial function and increasing the contents of smooth muscle and pericytes.

Male late-onset hypogonadism is an age-related disease, the core mechanism of which is dysfunction of senescent Leydig cells. Recent studies have shown that elimination of senescent cells can restore proper homeostasis to aging tissue. In the present study, we found that the fork head box O (FOXO) transcription factor FOXO4 was specially expressed in human Leydig cells and that its translocation to the nucleus in the elderly was related to decreased testosterone synthesis. Using hydrogen peroxide-induced senescent TM3 Leydig cells as an in vitro model, we observed that FOXO4 maintains the viability of senescent Leydig cells and suppresses their apoptosis. By disrupting the FOXO4-p53 interaction, FOXO4-DRI, a specific FOXO4 blocker, selectively induced p53 nuclear exclusion and apoptosis in senescent Leydig cells. In naturally aged mice, FOXO4-DRI improved the testicular microenvironment and alleviated age-related testosterone secretion insufficiency. These findings reveal the therapeutic potential of FOXO4-DRI for the treatment of male late-onset hypogonadism.

As testicular mesenchymal stromal cells, stem Leydig cells (SLCs) show great promise in the treatment of male hypogonadism. The therapeutic functions of mesenchymal stromal cells are largely determined by their reciprocal regulation by immune responses. However, the immunoregulatory properties of SLCs remain unclear. Here, we observe that SLCs transplantation restore male fertility and testosterone production in an ischemia‒reperfusion injury mouse model. SLCs prevent inflammatory cascades through mitochondrial transfer to macrophages. Reactive oxygen species (ROS) released from activated macrophages inducing mitochondrial transfer from SLCs to macrophages in a transient receptor potential cation channel subfamily member 7 (TRPM7)-mediated manner. Notably, knockdown of TRPM7 in transplanted SLCs compromised therapeutic outcomes in both testicular ischemia‒reperfusion and testicular aging mouse models. These findings reveal a new mechanism of SLCs transplantation that may contribute to preserve testis function in male patients with hypogonadism related to immune disorders.

The aim of this study was to investigate whether intracavernous injection of urine-derived stem cells (USCs) or USCs genetically modified with pigment epithelium-derived factor (PEDF) could protect the erectile function and cavernous structure in a bilateral cavernous nerve injury-induced erectile dysfunction (CNIED) rat model. USCs were cultured from the urine of six healthy male donors. Seventy-five rats were randomly divided into five groups ( n = 15 per group): sham, bilateral cavernous nerve (CN) crush injury (BCNI), USC, USC^GFP+, and USC^GFP/PEDF+groups. The sham group received only laparotomy without CN crush injury and intracavernous injection with phosphate-buffered saline (PBS). All of the other groups were subjected to BCNI and intracavernous injection with PBS, USCs, USCs^GFP+, or USCs^GFP/PEDF+, respectively. The total intracavernous pressure (ICP) and the ratio of ICP to mean arterial pressure (ICP/MAP) were recorded. The penile dorsal nerves, the endothelium, and the smooth muscle were assessed within the penile tissue. The USC and USC^GFP/PEDF+groups displayed more significantly enhanced ICP and ICP/MAP ratio ( p < 0.05) 28 days after cell transplantation. Immunohistochemistry (IHC) and Western blot analysis demonstrated that the protection of erectile function and the cavernous structure by USCs^GFP/PEDF+was associated with an increased number of nNOS-positive fibers within the penile dorsal nerves, improved expression of endothelial markers (CD31 and eNOS) and a smooth muscle marker (smoothelin), an enhanced smooth muscle to collagen ratio, decreased expression of transforming growth factor-β1 (TGF-β1), and decreased cell apoptosis in the cavernous tissue. The paracrine effect of USCs and USCs^GFP/PEDF+prevented the destruction of erectile function and the cavernous structure in the CNIED rat model by nerve protection, thereby improving endothelial cell function, increasing the smooth muscle content, and decreasing fibrosis and cell apoptosis in the cavernous tissue.