The reconstruction of genitourinary tract, affected by pathologies that require repair or replacement, is one of the current challenges in regenerative medicine. The use of stem cells (SCs) and platelet rich plasma (PRP), in the urological field, seems to be very promising, as showed by several animal and human studies [1,2]. Two different strategies of regeneration can be derived from SCs: Cell therapy and Tissue therapy (mainly through tissue engineering). Cell therapy relies on the injection of autologous or allogeneic cells or their secretome/conditioned medium to allow the regeneration of the tissues. On the other hand, tissue therapy relies on implantation of a synthetic or natural biomaterial, seeded or not with cells and eventually including growth factors, to improve and guide the repair process. Following, we will give an overview of SCs and PRP sources for urologic regenerative medicine, and in particular on their use in interstitial cystitis/bladder pain syndrome (IC/BPS) treatment.

Sources of Stem Cells for Regenerative Medicine in Urogenital Defects

As for cells, in urogenital applications, it is possible the use of autologous urothelial cells (UCs), when they are available. Multipotent cells or differentiated primary cells can be obtained from tissue biopsies [3], although for many diseases, autologous cells may not be used, as for example, for bladder and urothelial cancer, that are the most common causes of bladder oblation. Therefore, considering that some conditions reduce the autologous cell usage in clinical applications, a new source of accessible cells, with plasticity potential and high proliferation, is required. SCs, including adult SCs and PSCs, such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), possess the abilities of self-renewal, proliferation, and differentiation into various cell types. The therapeutic effects of SCs have been extensively researched and preclinically trialed in many urological diseases [4-8] including IC/BPS [9,10]. For these features, adult SCs are ideal candidates for tissue engineering targets [11-14]. Although ESCs are attractive in regenerative medicine, several problems in methodology and control of differentiation (teratoma development and long-term possibility of carcinogenesis), together with ethical and regulatory issues, limit their use [15].

Thus, somatic SCs are less controversial cells and they have a wide differentiation potential. According to the recent results, hair follicles may work as a source of accessible multipotent SCs that can be easily used in therapeutic approaches [16]. The other important source is represented by mesenchymal stem cells (MSCs), which are multipotent SCs that are isolated from adult tissues (e.g., bone marrow, peripheral blood, umbilical cord blood, adipose tissue, and dental pulp) [17-21]. MSCs injected intravesically or directly into bladder wall ameliorated bladder voiding dysfunction and inflammation, reduced nociceptive behavior, and decreased urothelial damage in rat IC models [22,23]. These SCs are stable in culture and have the potency to differentiate into cell types presenting features of various lineages, such as endothelial cells, epithelial cells (including urothelial cells), myoblasts, smooth muscle cells (SMCs), fibroblasts or neurogenic cells (1), [24]. The possibility of differentiating adipose SCs also into SMCs make them an interesting source in urogenital filed. Recently, urine-derived stem cells (USCs), expressing mesenchymal and pericyte cell markers [24,25] and displaying the capacity for multipotent differentiation, were also used. They can form multilayered tissue-like structures consisting of urothelium and smooth muscles in vivo [26]. Li et al. showed that USCs treatment significantly ameliorated urodynamic, inflammatory, oxidative, and apoptotic changes in PS/LPS- induced IC in female SD rats, compared to untreated controls [27]. Recently, Chung et al. compared the therapeutic potency of rat MSCs derived from different sources like urine, bone marrow, adipose tissue, and amniotic fluid, which showed no significant differences in the regeneration of urothelium and smooth muscle. However, URCs showed superior anti-inflammatory properties, compared to SCs derived from other sources [28]. Human dental pulp SCs (DP-SCs) are also of interest in the urological field, as shown by the successful differentiation of DP-SCs into bladder myogenic cells [29,21]. Moreover, studies have shown that somatic SCs can be obtained also from testes throughout the male lifetime [30], while other reports have shown that even endometrial SCs (EnSCs) could be differentiated into SMCs and urothelial cells for bladder engineering [31].

Platelet Rich Plasma (PRP) Source for Regenerative Medicine in Urogenital Defects

The other tool that regenerative medicine has been using successfully is represented by PRP [32], an autologous or allogeneic derivative of whole blood that contains a supraphysiological (three to five times higher than the baseline) concentration of thrombocytes in whole blood [33]. Platelets are formed in the bone marrow from megakaryocytes with a life span of about 7-10 days. They are small and discoid cells without nucleus, therefore they cannot reproduce. The main function of platelets is to contribute to homeostasis through 3 processes: adhesion, activation, and aggregation [34]. When a vascular lesion is present, platelets are activated, and their P-granules (alpha, delta, lambda) release factors that promote coagulation. Besides the hemostatic properties capable of inducing fibrin generation, new PRP properties have been discovered in recent years; among them anti-inflammatory and immunomodulation properties, as well as cell proliferation capacity [35]. Hence, PRP is a natural source of signaling molecules, upon activation of the platelets, the P- granules are degranulated, releasing growth factors and cytokines that modify the pericellular microenvironment [34]. Some of the most abundant growth factors released by platelets in PRP are: platelet-derived growth factor (PDGF), VEGF, fibroblast growth factor (FGF), epithelial growth factor (EGF), transforming grow factor β (TGFβ), hepatocyte growth factor (HGF), insulin-like factor 1 and 2 (IGF-1, IGF-2), matrix metalloproteinase (MMP) 2 and 9, and IL-8 [34,36,37]. These factors can promote local angiogenesis, stem cell homing, local cell migration, proliferation and differentiation, coupled with the deposition of matrix proteins, such as collagen, which all play a key role in enabling the restoration of normal tissue structure and function [38]. The interest and use of the regenerative properties of platelets have increased significantly in many different fields of medicine. In Gynecology and Reproductive medicine PRP are used for the treatment of infertility, erectile dysfunction in sexual dysfunction and vaginal atrophy [39-42]. PRP therapy may also have therapeutic potentials on several bladder disorders that are caused by defective urothelial regenerative function and urothelial cell differentiation, such as recurrent bacterial cystitis, radiation cystitis, chemical cystitis, as well as bladder disorders due to systemic diseases [43,44]. PRP has been shown to be effective also in the postprostatectomy urinary incontinence [45]. Furthermore, in a condition of inflammation and urothelial defects, as in IC/PBS, PRP administration into the bladder urothelium may override the unsolved inflammatory pattern, promote the wound healing process, increase tissue regeneration and lead to the relief of neurogenic pain [46]. Recently, innovative studies about the role played by platelets in regulating inflammation processes associated with cancer and thrombosis, have indicated that tumor-induced platelet activation reemerges as an important therapeutic target specifically to treat also bladder cancer [47].

IC/BPS Diagnosis and Cystoscopy

After the first definition of interstitial cystitis by Skene, in 1887, the physician that better characterized the syndrome was Hunner, who described a symptom complex of bladder pain associated with a peculiar cystoscopy feature of mucosal lesions, the ‘elusive ulcer’, later termed Hunner’s ulcer [48]. Since definition of the generic concept, the scope of IC became wider and more varied, and in order to achieve a standard for use in scientific studies, the US National Institute of Diabetes, Digestive and Kidney disorders (NIDDK), in 1987 defined a number of criteria mainly based on exclusions [49]. Overall, IC/BPS essentially represents a syndrome with quite varying contents, which generate confusion both in the definition of patho-physiological mechanisms and in the therapeutic options to gain symptom relief. Current consensus suggests that the ulcerative form is denoted ‘interstitial cystitis’ (IC) and the nonulcerative form ‘bladder pain syndrome’ (BPS) [50,51]. Under Cystoscopy the presence of submucosal petechial bleeding, so called glomerulations, after decompression of the previously distended bladder has, until recently, been regarded as one of the endoscopic hallmarks of the disease [52]. The typical lesion is a circumscribed, reddened mucosal area with small vessels radiating towards a central scar, with a fibrin deposit or coagulum attached to this area. On further bladder distension this site ruptures with petechial hemorrhage from the lesion and the mucosal margins in a waterfall manner [53]. A quite characteristic finding at the second filling of the bladder in a patient with this classic type of lesion is a varying degree of edema, sometimes with peripheral extension that frequently do not parallel the type or severity of symptoms, nor the subsequent response to treatment.

Etiology and Pathophysiology of IC/BPS

There is no doubt that the key to the diagnosis of IC is a careful history with identification of the characteristic symptoms, especially severity of pain and discomfort [54]. The classic description is an imperative urge on bladder filling with increasing suprapubic pain that extends throughout the pelvis, which in many instances is severe, relieved by voiding, although soon returning. Other descriptions of the sensation are ‘pressure’, ‘burning’, ‘sharp’, and ‘discomfort’[55-57]. Although bladder pain and urinary frequency may be the only or major complaints in some individuals, others have a broader spectrum of problems, including associations of IC to allergy, fibromyalgia, vulvodynia, chronic fatigue syndrome, anxiety disorders, and depression. Such associations should be acknowledged in the patient’s history. To investigate the mechanism of stress implicated in IC/BPS, recently Jhang et al. [58], investigated expression of stress-response corticotropin-releasing hormone receptor (CRHR) in bladder from IC/BPS patients. Specifically they enrolled 23 IC/BPS patients with Hunner’s lesion (HIC) [59], 51 IC/BPS patients without Hunner’s lesion (NHIC), and 24 patients with stress urinary incontinence as controls. Data collected revealed that CRHR1 expression was mainly located in the submucosa while CRHR2 expression was mainly in uroepithelial cells. Compared to control subjects, the CRHR1 expression was significantly higher, while CRHR2 expression was significantly lower in IC/BPS patients. Further analysis of patients with HIC, NHIC, and control subjects showed that bladder, in patients with HIC, had significantly higher expressions of CRHR1 and significantly lower CRHR2. CRHR2 expression was significantly negatively correlated with O’Leary-Sant score and bladder pain. These results would indicate dysregulation of bladder CRHR1 and CRHR2 in patients with IC/BPS, and suggest that CRH signaling may contribute to IC/BPS symptoms [58]. As already mentioned it has been found that patients who have IC/BPS have also high rates of anxiety as a comorbid condition [60]. Also data in mice showed that acute stress induces bladder vascular permeability and vascular endothelial growth factor (VEGF) release that is dependent on CRHR2, suggesting that CRH and VEGF might participate in the pathogenesis of IC/PBS [61]. All these data are consistent with the evidence that CRH, CRH-related peptides and their receptors are present in the central nervous system and in a wide variety of peripheral tissues, including the immune [62], cardiovascular and reproductive systems, and associated with the pathophysiology of many disease states [63], including IC/PBS.

Histopathology and NO Role in IC/BPS

Although the histopathologic features are not distinctive in non- ulcer disease, there are microscopic findings pathognomonic for classic IC. These include urothelial vacuolization and detachment, mucosal infiltrates of lymphocytes, plasma cells, neutrophil, and eosinophil granulocytes, as well as an increase of mast cell numbers in all compartments of the bladder wall [64]. Granulation tissue is one further feature of the classic disease, speculatively as a result of repeated trauma by bladder filling and stretch of the areas of inflammatory involvement. It is reasonable to hypothesize that the various components of the cell infiltrate play various roles, although they are yet poorly characterized [65]. For example, studies suggest that T cells and B cells are associated with various clinical features of IC and moreover there are marked differences in lymphocyte populations in classic versus non-ulcer disease, while macrophages have a possible role in the massive production of nitric oxide (NO) seen in the Hunner-type of disease [66]. NO is a physiological mediator that regulates vascular function and inflammation and acts as a neurotransmitter also in the bladder [67]. However, when the homeostasis of the oxygen-oxidation reaction is not well balanced (as during stress condition), NO may be converted into pro- inflammatory and cytotoxic substances through the formation of reactive nitrogen species (RNS) products [68]. It has been shown that patients with non-ulcerous IC did not have elevated levels of NO compared to those with classic IC [69]. Moreover it was reported that the NO concentration decreased in patients treated with steroids and that it correlated to a decrease in symptom score in these patients [70]. It is interesting to highlight that in the brain interleukin (IL)-2, by stimulation of cholinergic neurons, activates neural nitric oxide synthase (NOS). The NO released diffuses into corticotropin-releasing hormone (CRH)- secreting neurons and releases CRH [71]. Previously we have mentioned the work by Jhang et al., showing that in IC/BPS patients CRHR1 expression was significantly higher, while CRHR2 expression was significantly lower compared to control subjects. Because CRHRs are important mediators in the stress response [63], it would be worthy to investigate the connection between the NO produced by macrophages in the bladder and the HPA axis regulation, where CRH plays its role by binding CRHRs. Moreover, special interest has been devoted to the mast cell, supposed to be a major player in this disease complex, involving the diagnosis, development of symptoms, and relation to detrusor fibrosis, to give some examples [72]. Mast cells can be activated by a variety of agents, leading to release of a number of distinct inflammatory mediators, with or without degranulation [73]. How these differential mast cell responses are controlled is still unresolved. It appears also interesting to point out that the mast cell is a major target of immune CRH. Beside the central, hypothalamic CRH that influences the immune system indirectly through activation of the end products of the peripheral stress response, it is also secreted peripherally at inflammatory sites (peripheral or immune CRH) and influences the immune system directly through local modulatory actions [74,62], as already mentioned before. This aspect would also link the HPA axis regulation and the NO produced by macrophages in the bladder under the control of mast cell. Therefore investigating cause and effect in different bladder wall cellular responses is required to be able to reveal the nature of various BPS/IC phenotypes [75].

Standard Treatments for IC/BPS

No efficacy curative conservative treatment has yet been identified for IC. No single treatment works for all people with IC, therefore treatment must be chosen for each patient based on symptoms. Patients usually try different treatments (or combinations of treatments) until good symptom relief occurs. It is important to know that none of these IC treatments works right away and usually it takes weeks to months before symptoms improve. Even with successful treatment, the condition may not be cured [76,77].

Use of Stem Cells in IC/BPS

In patients with IC/BPS, as already discussed, the bladder has been found to have an increased number of mast cells, which release inflammatory mediators such as histamine and cytokines in response to activation [72]. In addition, the urothelium can release a number of neural signaling molecules, such as adenosine triphosphate and nerve growth factor (NGF), which subsequently activate submucosal afferent nerves and mast cells [78,79]. The initial concept of using SCs for IC/BPS was based on the hypothesis that SCs transplantation into the bladder might replenish the damaged epithelium and neurons [80]. However, more recently, another hypothesis has emerged, according to which transplanted SCs might provide therapeutic benefits through the paracrine release of anti-inflammatory, pro-angiogenic, antiapoptotic, and/or antioxidative factors, including exosomes [81-83]. Furthermore, these paracrine bioactive factors are also believed to have the ability to enhance the expression of stem cell trafficking genes, leading to the recruitment of endogenous SCs to the damaged tissues [84]. In addition, MSCs are known to possess immunomodulatory properties, therefore, they can be transplanted allogeneically or xenogeneically into immunocompetent recipients without the use of immunosuppressants [85]. We believe that the understanding of the molecular mechanism underlying SCs action in bladder disease is important to improve their therapeutic effect against IC/BPS. In 2017, Kim et al. reported on the potential use of hESC-derived multipotent mesenchymal SCs (M-MSC) in IC/BPS in animals, with evidence for long-term safety (6 months after transplantation). M-MSCs therapy significantly ameliorated defects in bladder voiding function, reduced visceral hypersensitivity, and expressed superior therapeutic potency compared to adult bone marrow-derived mesenchymal SCs given in the same doses [86]. The results were later confirmed by Lee et al. in the ketamine-induced chronic IC rat model [87]. Intravital imaging of transplanted hESC-derived M-MSCs in PS/LPS-induced rat IC model demonstrated migration of GFP-transfected M-MSCs from the injection site (serosa andmuscle layer) to the damaged urothelium and lamina propria, followed by differentiation into various cell types, which correlated with improvement of IC/BPS symptoms [88]. However, although the preclinical studies mark SCs as favorable in IC/BPS treatment, due to the lack of reliable tracking molecules/reagents to demonstrate engraftment and/or differentiation of transplanted SCs, the therapeutic mechanism of SCs remains controversial and the results of animal studies should be carefully interpreted and critically evaluated before designing clinical trials [89,77]. At present, the paracrine effects of transplanted SCs seem to be more prominent because of their stimulation of the host’s own SCs and adjacent cells [80,90]. To date, only one clinical trial has assessed the efficacy of SCs for IC/BPS. In 2019, Lander et al. [91] investigated the effect of combined intravenous and local injections of autologous stromal vascular fraction (SVF) into the pelvic floor in 91 women and 18 men with IC/BPS. SVF may reduce the level of inflammation, as indicated by lower expression of inflammatory cytokines and higher expression of anti-inflammatory cytokines (lower IL-6 and TNF-α expression and higher IL-10 expression and M2 macrophage numbers) [92-94]. SVF when interact with lymphocytes displays potent immunosuppressive and anti-inflammatory effects, negatively regulating T cell, B cell, NK cell proliferation, and maturation of dendritic cells [95]. Moreover as reported by Kim et al., SVF contain IGF, pigment epithelium-derived factor (PEDF), secreted super-oxide dismutase (SOD), and glutathione peroxidase (GPX), as protective agents against free radical [96]. The study of ander et al. demonstrated that SVF, as an autologous personalized regenerative strategy, howed good safety and efficacy, and may have the potential to alleviate IC/BPS. However, the major limitations were the lack of a control group, inconsistent transplantation cell number, inconsistent cell injection routes in male patients, lack of information on the molecular mechanisms of SVF therapy and the absence of long-term data [91]. Therefore larger, multicenter, long-term, randomized clinical trials are needed to elucidate the efficiency of SVF in patients with IC/BPS [89].

Use of PRP in IC/BPS

PRP contains numerous growth and cytokines that potentially offer an alternative treatment modality to assist in the healing of bladder mucosa injuries [44]. The precise mechanism by which PRP promotes bladder healing in IC/BPS is not fully understood. As discussed above IC may result from urothelial barrier dysfunction, which initiates a cascade of neurogenic inflammation [44]. As a result, chronic inflammation and bladder fibrosis would elicit bladder pain and a small bladder capacity [89]. PRP injections into the bladder might provide several growth factors that promote cell proliferation, regeneration, and differentiation to heal the damaged urothelium; they may also activate an additional inflammatory signaling by its cytokines and leukocytes, switching to an anti-inflammatory phenotype and releasing anti-inflammatory factors and anxiolytic factor as serotonin [60]. Thus, PRP injections into the bladder might enhance tissue angiogenesis and eliminate refractory neuropathic pain. In one Clinical Trial (ClinicalTrial.gov: NCT03104361; IRB: TCGH 105-48-A.) Jhang et al. [97,98] investigated the changes in urinary markers after PRP treatment. Forty patients (37 women and 3 men, aged 55.5 ± 11.1 years) with IC/BPS who were refractory to conventional therapy who had previously failed to conventional treatments (including lifestyle modifications, cystoscopic hydrodistention, non-steroid anti-inflammatory drugs, oral Pentosan Polysulfate, tricyclic antidepressants, intravesical instillation of hyaluronic acid, or botulinum toxin A injection), received four injections of PRP at monthly intervals. Specifically, 10 ml PRP solution with 2.5 times the peripheral blood platelet concentration was used. Urine levels of thirteen functional proteins, growth factors, and cytokines were assessed at baseline and at the 4^th PRP injection. The clinical parameters included visual analog scale (VAS) pain score, daily urinary frequency, nocturia episodes, functional bladder capacity, and global response assessment (GRA). The GRA and symptom score significantly decreased post-treatment. In patients with GRA ≥ 2, the success rates at 1 month and at 3 months after the 4^th PRP injection were 70.6% and 76.7%, respectively. The VAS pain score, frequency, and nocturia showed a significant decrease. Urinary levels of NGF, MMP-13, and VEGF significantly decreased post-treatment; PDGF-AB showed a significant increase at the 4th PRP treatment compared with baseline. In another recent clinical trial the same authors showed significant improvements in urothelial tight junction defects in patients with refractory non-ulcer IC/BPS [99]. Therefore, considering that one of the most relevant pathophysiological mechanisms of interstitial cystitis is the increase in urothelial permeability related to proteoglycan deficiency the use of PRP has a consistent rationale and may be clinically useful as well as relatively cheap and easy to prepare as already described.

It still remains unknown whether high levels of NO are a part of the pathophysiological mechanisms behind IC, and whether they have protective or damaging role in this disease. Anyhow, one can conclude that measuring NO produced in the urinary bladder provide a new tool for differentiating between IC and painful bladder symptoms from other etiology. From the studies analyzed, it seems obvious that the oxidative stress is an underlying mechanism in the pathophysiology of IC/BPS, where the biological damage may be produced as consequence of an overwhelmed antioxidant capacity. The presence of CRHRs in the bladder and their dysregulation in patients with IC/BPS, suggest that CRH signaling may be associated with IC/BPS symptoms, with a consequent important role played by stress in this pathology. In fact, if there is a permanent harmful challenge as an autoimmune disease, in response to inflammation, the activated HPA axis modulates through CRH release, the immune responses via glucocorticoid activity, with an associated strong imbalance in the redox homeostasis [100]. As described afore the mast cells are the main target of immune CRH and mast cells may activate other immune cells as macrophages. Accordingly, this imbalance and the consequent increase of oxidant production may induce the conversion of NO that is produced by macrophages as a toxic defense molecule against infectious organism into pro- inflammatory and cytotoxic substance through the formation of RNS products. This overproduction of ROS and RNS produced by immune cells leads to cell membrane destruction with the consequent uroepithelial damages (Figure 1).

Figure 1: SVF and PRP release factors that protect and repair the damaged bladder. The presence of CRHRs in the bladder and their dysregulation in patients with IC/BPS, suggest that CRH signaling might be associated with IC/BPS symptoms, with a consequent important role played by stress in this pathology. When there is a permanent harmful challenge, represented by the dysregulation in the stress response, the redox homeostasis is not well balanced. This imbalance and the consequent increase of oxidant production may induce the conversion of NO that is produced by inflammatory cells into pro- inflammatory and cytotoxic substance, through the formation of RNS products. Overproduction of ROS and RNS leads to cell membrane destruction with the consequent uroepithelial damages. SVF may reduce the level of inflammation, as indicated by higher expression of anti-inflammatory cytokines and M2 macrophage numbers. Moreover, SVF contains IGF, PEDF, SOD, and GPX, as protective agents against free radical. All these activities may assist in reducing ROS-induced damage. On the other hand, PRPs play an important role in the tissue repair mainly due to the many growth factors they contain, as PDGF and IGF-I that inhibit the apoptotic pathway during cell turnover and facilitate different stages of wound healing. PRPs contain also anxiolytic factor as serotonin, which decreases pain.

level of inflammation, as indicated by lower expression of inflammatory cytokines, higher expression of anti-inflammatory cytokines (lower IL-6 and TNF-α expression and higher IL-10 expression and M2 macrophage numbers), negative regulation of T cells, B cells, NK cell proliferation and maturation of dendritic cells, and ability to decrease the myeloperoxidase. Moreover, SVF contains IGF, PEDF, SOD, and GPX, as protective agents against free radical. All these activities described may assist in reducing ROS-induced damage. On the other hand, PRPs play an important role in the tissue repair mainly due to many growth factors, as PDGF and IGF-I that inhibit the apoptotic pathway during cell turnover and facilitate different stages of wound healing. PRPs contain also pain-reducing factors as serotonin. Moreover, as discussed afore, it has been shown that the combination of both SVFs and PRP, in rat model, has the ability to accelerate epithelialization, induce angiogenesis, stimulate fibroblasts and inhibit the local and systemic stress oxidative response, as indicated by the decreased NO levels, in blood serum and tissue, in deep dermal burn wound injuries. Considering all these evidences, the combination of SVF and PRP, because intravesical injection under anesthesia is safe and simple, could be potential alternative treatment for IC/BPS patients.

1. Caneparo C, Sorroza-Martinez L, Chabaud S, Fradette J, Bolduc S. Considerations for the clinical use of stem cells in genitourinary regenerative medicine. World J Stem Cells. 2021; 13: 1480-1512.
2. Chiang CH, Kuo HC. The Efficacy and Mid-term durability of urethral sphincter injections of Platelet-Rich plasma in treatment of female stress urinary incontinence. Front Pharmacol. 2022; 13.
3. Raya-Rivera A, Esquiliano DR, Yoo JJ, Lopez-Bayghen E, Soker S, Atala A. Tissue- engineered autologous urethras for patients who need reconstruction: An observational study. Lancet. 2011; 377: 1303-1304.
4. Nakajima N, Tamaki T, Hirata M, Soeda S, Nitta M, Hoshi A, et al. Purified human skeletal Muscle-Derived stem cells enhance the repair and regeneration in the damaged urethra. Transplantation. 2017; 101: 2312-2320.
5. Kim JH, Yang HJ, Choi SS, Kim SU, Lee HJ, Song YS. Improved bladder contractility after transplantation of human mesenchymal stem cells overexpressing hepatocyte growth factor into underactive bladder from bladder outlet obstruction models of rats. PLoS One. 2021; 16.
6. Mamillapalli R, Cho SH, Mutlu L, Taylor HS. Therapeutic role of uterine-derived stem cells in acute kidney injury. Stem Cell Res Ther. 2022; 13.
7. Salemi S, Prange JA, Baumgartner V, Mohr-Haralampieva D, Eberli D. Adult stem cell sources for skeletal and smooth muscle tissue engineering. Stem Cell Research and Therapy. 2022; 13.
8. Liang CC, Shaw SW, Huang YH LT. Human amniotic fluid stem cell therapy can help regain bladder function in type 2 diabetic rats. World J Stem Cells. 2022; 14: 330-346.
9. Dayem AA, Kim K, Lee S Bin, Kim A, Cho SG. Application of adult and pluripotent stem cells in interstitial cystitis/bladder pain syndrome therapy: Methods and perspectives. Journal of Clinical Medicine. 2020; 9.
10. Xu Y, Yang F, Xie J, Li W, Liu B, Chen J, et al. Human umbilical cord mesenchymal stem cell therapy mitigates interstitial cystitis by inhibiting mast cells. Med Sci Monit. 2021; 27.
11. Sharma AK, Hota P V, Matoka DJ, Fuller NJ, Jandali D, Thaker H, et al. Urinary bladder smooth muscle regeneration utilizing bone marrow derived mesenchymal stem cell seeded elastomeric poly(1,8-octanediol-co-citrate) based thin films. Biomaterials. 2010; 31: 6207-6217.
12. Guan Y, Liu S, Sun C, Cheng G, Kong F, Luan Y, et al. The effective bioengineering method of implantation decellularized renal extracellular matrix scaffolds. Oncotarget. 2015; 6: 36126-36138.
13. Lee JN, Chun SY, Lee HJ, Jang YJ, Choi SH, Kim DH, et al. Human urine-derived stem cells seeded surface modified composite scaffold grafts for bladder reconstruction in a rat model. J Korean Med Sci. 2015; 30: 1754-1763.
14. Yudintceva NM, Nashchekina YA, Mikhailova NA, Vinogradova TI, Yablonsky PK,Gorelova AA, et al. Urethroplasty with a bilayered poly-D,L-lactide-co-ε-caprolactone scaffold seeded with allogenic mesenchymal stem cells. J Biomed Mater Res - Part B Appl Biomater. 2020; 108: 1010-1021.
15. Lo B, Parham L. Ethical issues in stem cell research. Endocrine Reviews. 2009; 30: 204–213.
16. Tsao CK, Ko CY, Yang SR, Yang CY, Brey EM, Huang S, et al. An ectopic approach for engineering a vascularized tracheal substitute. Biomaterials. 2014; 35: 1163-1175.
17. Murphy MB, Moncivais K, Caplan AI. Mesenchymal stem cells: Environmentally responsive therapeutics for regenerative medicine. Experimental and Molecular Medicine. 2013; 45.
18. Bury MI, Fuller NJ, Sturm RM, Rabizadeh RR, Nolan BG, Barac M, et al. The effects of bone marrow stem and progenitor cell seeding on urinary bladder tissue regeneration. Sci Rep. 2021; 11.
19. Xie J, Liu B, Chen J, Xu Y, Zhan H, Yang F, et al. Umbilical cord-derived mesenchymal stem cells alleviated inflammation and inhibited apoptosis in interstitial cystitis via AKT/mTOR signaling pathway. Biochem Biophys Res Commun. 2018; 495: 546-552.
20. Pokrywczynska M, Rasmus M, Jundzill A, Balcerczyk D, Adamowicz J, Warda K, et al. Mesenchymal stromal cells modulate the molecular pattern of healing process in tissue-engineered urinary bladder: The microarray data. Stem Cell Res Ther. 2019; 10.
21. Zordani A, Pisciotta A, Bertoni L, Bertani G, Vallarola A, Giuliani D, et al. Regenerative potential of human dental pulp stem cells in the treatment of stress urinary incontinence: In vitro and in vivo study. Cell Prolif. 2019; 52: e12675.
22. Hirose Y, Yamamoto T, Nakashima M, Funahashi Y, Matsukawa Y, Yamaguchi M, et al. Injection of dental pulp stem cells promotes healing of damaged bladder tissue in a rat model of chemically induced cystitis. Cell Transplant. 2016; 25: 425-436.
23. Furuta A, Yamamoto T, Igarashi T, Suzuki Y, Egawa S, Yoshimura N. Bladder wall injection of mesenchymal stem cells ameliorates bladder inflammation, overactivity, and nociception in a chemically induced interstitial cystitis-like rat model. Int Urogynecol J. 2018; 29: 1615-1622.
24. Keshel SH, Rahimi A, Hancox Z, Ebrahimi M, Khojasteh A, Sefat F. The promise of regenerative medicine in the treatment of urogenital disorders. J Biomedical Materials Res - Part A. 2020; 108: 1747-1759.
25. Orlando G, Soker S, Stratta RJ. Organ bioengineering and regeneration as the new holy grail for organ transplantation. Annals of Surgery. 2013; 258: 221-232.
26. Bharadwaj S, Liu G, Shi Y, Wu R, Yang B, He T, et al. Multipotential differentiation of human urine-derived stem cells: Potential for therapeutic applications in urology. Stem Cells. 2013; 31: 1840-1856.
27. Li J, Luo H, Dong X, Liu Q, Wu C, Zhang T, et al. Therapeutic effect of urine-derived stemcells for protamine/lipopolysaccharide-induced interstitial cystitis in a rat model. Stem Cell Res Ther. 2017; 8.
28. Chung JW, Chun SY, Lee EH, Ha YS, Lee JN, Song PH, et al. Verification of mesenchymal stem cell injection therapy for interstitial cystitis in a rat model. PLoS One. 2019; 14.
29. Song B, Jiang W, Alraies A, Liu Q, Gudla V, Oni J, et al. Bladder smooth muscle cells differentiation from dental pulp stem cells: Future potential for bladder tissue engineering. Stem Cells Int. 2016.
30. De Chiara L, Famulari ES, Fagoonee S, Van Daalen SKM, Buttiglieri S, Revelli A, et al. Characterization of human mesenchymal stem cells isolated from the testis. Stem Cells Int. 2018.
31. Shoae-Hassani A, Mortazavi-Tabatabaei SA, Sharif S, Seifalian AM, Azimi A, Samadikuchaksaraei A, et al. Differentiation of human endometrial stem cells into urothelial cells on a three-dimensional nanofibrous silk-collagen scaffold: An autologous cell resource for reconstruction of the urinary bladder wall. J Tissue Eng Regen Med. 2015; 9: 1268-1276.
32. Etulain J, Mena HA, Meiss RP, Frechtel G, Gutt S, Negrotto S, et al. An optimised protocol for platelet-rich plasma preparation to improve its angiogenic and regenerative properties. Sci Rep. 2018; 8.
33. Knezevic NN, Candido KD, Desai R, Kaye AD. Is Platelet-Rich Plasma a Future Therapy in Pain Management? Medical Clinics of North America. 2016; 100: 199-217.
34. Alves R, Grimalt R. A Review of Platelet-Rich plasma: History, biology, mechanism of action, and classification. Skin Appendage Disorders. 2018; 4: 18-24.
35. Luzo ACM, Fávaro WJ, Seabra AB, Durán N. What is the potential use of platelet-rich- plasma (PRP) in cancer treatment? A mini review. Heliyon. 2020; 6.
36. Lubkowska A, Dolegowska B, Banfi G. Growth factor content in PRP and their applicability in medicine. Journal of biological regulators and homeostatic agents. 2012; 26.
37. Andia I, Abate M. Platelet-rich plasma: Underlying biology and clinical correlates. Regenerative Medicine. 2013; 8.
38. Harrison P, Alsousou J, Andia I, Burnouf T, Dohan Ehrenfest D, Everts P, et al. The use of platelets in regenerative medicine and proposal for a new classification system: guidance from the SSC of the ISTH. J Thromb Haemost. 2018; 16: 1895-1900.
39. Alkandari MH, Touma N, Carrier S. Platelet-Rich plasma injections for erectile dysfunction and peyronie’s disease: A systematic review of evidence. Sexual Medicine Reviews. 2022; 10: 341-352.
40. Tas T, Cakiroglu B, Arda E, Onuk O, Nuhoglu B. Early clinical results of the tolerability, safety, and efficacy of autologous platelet-rich plasma administration in erectile dysfunction. Sex Med. 2021; 9: 100313.
41. Sharara FI, Lelea LL, Rahman S, Klebanoff JS, Moawad GN. A narrative review of platelet- rich plasma (PRP) in reproductive medicine. Journal of Assisted Reproduction and Genetics. 2021; 38: 1003-1012.
42. Hersant B, Sidahmed-Mezi M, Belkacemi Y, Darmon F, Bastuji-Garin S, Werkoff G, et al. Efficacy of injecting platelet concentrate combined with hyaluronic acid for the treatment of vulvovaginal atrophy in postmenopausal women with history of breast cancer: A phase 2 pilot study. Menopause. 2018; 25: 1124-1130.
43. irzaei M, Daneshpajooh A, Farsinezhad A, Jafarian Z, Ebadzadeh MR, Saberi N, et al. The Therapeutic effect of intravesical instillation of platelet rich plasma on recurrent bacterial cystitis in women: A randomized clinical trial. Urol J. 2019; 16: 609-613.
44. Ke QS, Jhang JF, Lin TY, Ho HC, Jiang YH, Hsu YH, et al. Therapeutic potential of intravesical injections of platelet-rich plasma in the treatment of lower urinary tract disorders due to regenerative deficiency. Tzu Chi Medical Journal. 2019; 31: 135-143.
45. Lee PJ, Jiang YH, Kuo HC. A novel management for postprostatectomy urinary incontinence: platelet-rich plasma urethral sphincter injection. Sci Rep. 2021; 11.
46. Kuffler DP. Platelet-rich plasma and the elimination of neuropathic pain. In: Molecular Neurobiology. 2013; 48: 315–332.
47. Dias LP, Luzo ÂCM, Volpe BB, Durán M, Galdames SEM, Ferreira LAB, et al. Effects of intravesical therapy with platelet-rich plasma (PRP) and Bacillus Calmette-Guérin (BCG) in non-muscle invasive bladder cancer. Tissue Cell. 2018; 52: 17-27.
48. Hunner GL. A rare type of bladder ulcer: Further notes, with a report of eighteen cases. J Am Med Assoc. 1918; 70: 203-212.
49. Gillenwater JY, Wein AJ. Summary of the National Institute of Arthritis, Diabetes, Digestive and Kidney Diseases Workshop on Interstitial Cystitis, National Institutes of Health, Bethesda, Maryland, August 28-29, 1987. The Journal of urology. 1988.
50. Leiby BE, Landis JR, Propert KJ, Tomaszewski JE. Discovery of morphological subgroups that correlate with severity of symptoms in interstitial cystitis: A Proposed Biopsy Classification System. J Urol. 2007; 177: 142-148.
51. Ian Eardley FCH. Oxford Textbook of Urological Surgery. In: Atlas of Surgical Anatomy. 2017.
52. Saha SK, Jeon T Il, Jang S Bin, Kim SJ, Lim KM, Choi YJ, et al. Bioinformatics approach for identifying novel biomarkers and their signaling pathways involved in interstitial cystitis/bladder pain syndrome with hunner lesion. J Clin Med. 2020; 9.
53. van de Merwe JP, Nordling J, Bouchelouche P, Bouchelouche K, Cervigni M, Daha LK, et al. Diagnostic Criteria, Classification, and nomenclature for painful bladder syndrome/Interstitial cystitis: An ESSIC Proposal. European Urology. 2008; 53: 60-67.
54. R. Bladder pain syndrome: symptoms, quality of life, treatment intensity, clinical and pathological findings and their correlationsNo Title. Det Sundhedsvidenskabelige Fakultet, KU. 2010.
55. Hanno PM, Erickson D, Moldwin R, Faraday MM. Diagnosis and treatment of interstitial cystitis/bladder pain syndrome: AUA guideline amendment. J Urol. 2015; 193.
56. Vij M, Srikrishna S, Cardozo L. Interstitial cystitis: Diagnosis and management. European J Obstetrics and Gynecology and Reproductive Biology. 2012; 161: 1-7.
57. Rosenberg MT, Newman DK, Page SA. Interstitial cystitis/painful bladder syndrome: symptom recognition is key to early identification, treatment. Cleveland Clinic J Med. 2007; 74.
58. Jhang JF, Birder LA, Jiang YH, Hsu YH, Ho HC, Kuo HC. Dysregulation of bladder corticotropin-releasing hormone receptor in the pathogenesis of human interstitial cystitis/bladder pain syndrome. Sci Rep. 2019; 9.
59. Whitmore KE, Fall M, Sengiku A, Tomoe H, Logadottir Y, Kim YH. Hunner lesion versus non-Hunner lesion interstitial cystitis/bladder pain syndrome. Int J Urology. 2019; 26: 26-34.
60. Hardy TJ. Interstitial cystitis can be improved with intravesical instillation of Platelet-Rich plasma. Cureus. 2022;14: 3-7.
61. Boucher W, Kempuraj D, Michaelian M, Theoharides TC. Corticotropin-releasing hormone-receptor 2 is required for acute stress-induced bladder vascular permeability and release of vascular endothelial growth factor. BJU Int. 2010; 106: 1394-1399.
62. Chrousos GP. Stress, chronic inflammation, and emotional and physical well-being: Concurrent effects and chronic sequelae. J Allergy Clin Immunol. 2000; 106: S275-S291.
63. Grammatopoulos DK, Chrousos GP. Functional characteristics of CRH receptors and potential clinical applications of CRH-receptor antagonists. Trends in Endocrinology and Metabolism. 2002; 14: 436-444.
64. Hamdy Freddie C. EI. Oxford Textbook of Urological Surgery. Oxford University Press;
65. Akiyama Y, Homma Y, Maeda D. Pathology and terminology of interstitial cystitis/bladder pain syndrome: A review. Histology and Histopathology. 2018; 34.
66. Lundberg JON, Ehrén I, Jansson O, Adolfsson J, Lundberg JM, Weitzberg E, et al. Elevated nitric oxide in the urinary bladder in infectious and noninfectious cystitis. Urology. 1996; 48: 700-702.
67. Birder L, Andersson KE. Urothelial signaling. Physiol Rev. 2013; 93.
68. Szabó C, Ischiropoulos H, Radi R. Peroxynitrite: Biochemistry, pathophysiology and development of therapeutics. Nature Reviews Drug Discovery. 2007; 6: 662-680.
69. Logadottir YR, Ehrén I, Fall M, Wiklund NP, Peeker R. Intravesical nitric oxide production discriminates between classic and nonulcer interstitial cystitis. J Urol. 2004; 171: 1148-1151.
70. Hosseini A, Ehrén I, Wiklund NP. Nitric oxide as an objective marker for evaluation of treatment response in patients with classic interstitial cystitis. J Urol. 2004; 172: 2261-2265.
71. McCann SM, Kimura M, Karanth S, Yu WH, Rettori V. Nitric oxide controls the hypothalamic-pituitary response to cytokines. Neuroimmunomodulation. 1997; 4: 98-106.
72. Peeker R, Enerbäck L, Fall M, Aldenborg F. Recruitment, distribution and phenotypes of mast cells in interstitial cystitis. J Urol. 2000; 163: 1009-1015.
73. Fall M, Logadottir Y, Peeker R. Interstitial cystitis is bladder pain syndrome with Hunner’s lesion. Int J Urol. 2014; 21: 79-82.
74. Chrousos GP. The Hypothalamic–Pituitary–Adrenal Axis and Immune-Mediated Inflammation. N Engl J Med. 1995; 332: 1351-1363.
75. Theoharides TC, Kempuraj D, Tagen M, Conti P, Kalogeromitros D. Differential release of mast cell mediators and the pathogenesis of inflammation. Immunological Reviews. 2007; 217: 65-78.
76. Colemeadow J, Sahai A, Malde S. Clinical management of bladder pain syndrome/interstitial cystitis: A review on current recommendations and emerging treatment options. Res Reports Urol. 2020; 12: 331-343.
77. Kuret T, Peskar D, Erman A, Verani? P. A systematic review of therapeutic approaches used in experimental models of interstitial cystitis/bladder pain syndrome. Biomedicines. 2021; 9.
78. Parsons CL, Greene RA, Chung M, Stanford EJ, Singh G. Abnormal urinary potassium metabolism in patients with interstitial cystitis. J Urol. 2005;173: 1182-1185.
79. Gonzalez RR, Fong T, Belmar N, Saban M, Felsen D, Te A. Modulating bladder neuro-inflammation: RDP58, a novel anti-inflammatory peptide, decreases inflammation and nerve growth factor production in experimental cystitis. J Urol. 2005; 173: 630-634.
80. Kim A, Shin DM, Choo MS. Stem Cell Therapy for Interstitial Cystitis/Bladder Pain Syndrome. Current Urology Reports. 2016; 17.
81. Park CW, Kim KS, Bae S, Son HK, Myung PK, Hong HJ, et al. Cytokine secretion profiling of human mesenchymal stem cells by antibody array. Int J Stem Cells. 2009; 2: 59-68.
82. Sun DZ, Abelson B, Babbar P, Damaser MS. Harnessing the mesenchymal stem cell secretome for regenerative urology. Nature Reviews Urology. 2019; 16: 363–375.
83. Wen C, Xie L, Hu C. Roles of mesenchymal stem cells and exosomes in interstitial cystitis/bladder pain syndrome. Journal of Cellular and Molecular Medicine. 2022; 26: 624-635.
84. Song M, Heo J, Chun JY, Bae HS, Kang JW, Kang H, et al. The paracrine effects of mesenchymal stem cells stimulate the regeneration capacity of endogenous stem cells in the repair of a bladder-outlet-obstruction- induced overactive bladder. Stem Cells Dev. 2014; 23: 654-663.
85. Lin CS, Lin G, Lue TF. Allogeneic and xenogeneic transplantation of adipose-derived stem cells in immunocompetent recipients without immunosuppressants. Stem Cells and Development. 2012; 21: 2770-2778..
86. Kim A, Yu HY, Lim J, Ryu CM, Kim YH, Heo J, et al. Improved efficacy and in vivo cellular properties of human embryonic stem cell derivative in a preclinical model of bladder pain syndrome. Sci Rep. 2017; 7.
87. Lee SW, Ryu CM, Shin JH, Choi D, Kim A, Yu HY, et al. The therapeutic effect of human embryonic stem cell-derived multipotent mesenchymal stem cells on chemical-induced cystitis in rats. Int Neurourol J. 2018; 22: S34-45.
88. Ryu CM, Yu HY, Lee HY, Shin JH, Lee S, Ju H, et al. Longitudinal intravital imaging of transplanted mesenchymal stem cells elucidates their functional integration and therapeutic potency in an animal model of interstitial cystitis/bladder pain syndrome. Theranostics. 2018; 8: 5610-5624.
89. Lin CC, Huang YC, Lee WC, Chuang YC. New frontiers or the treatment of interstitial cystitis/bladder pain syndrome-focused on stem cells, platelet-rich plasma, and low-energy shock wave. International Neurourology Journal. 2020; 24: 211-221.
90. Kim JH, Lee HJ, Song YS. Treatment of bladder dysfunction using stem cell or tissue engineering technique. Korean Journal of Urology. 2014; 55.
91. Lander EB, Berman MH, See JR. Personal cell therapy for interstitial cystitis with autologous stromal vascular fraction stem cells. Ther Adv Urol. 2019; 11.
92. Ramakrishnan VM, Boyd NL. The Adipose stromal vascular fraction as a complex cellular source for tissue engineering applications. Tissue Engineering - Part B: Reviews. 2018; 24.
93. Nava S, Sordi V, Pascucci L, Tremolada C, Ciusani E, Zeira O, et al. Long-Lasting Anti-Inflammatory activity of human microfragmented adipose tissue. Stem Cells Int. 2019.
94. Kumar S, Verma R, Tyagi N, Gangenahalli G, Verma YK. Therapeutics effect of mesenchymal stromal cells in reactive oxygen species-induced damages. Human Cell. 2022; 35: 37–50.
95. Wang M, Yuan Q, Xie L. Mesenchymal stem cell-based immunomodulation: Properties and clinical application. Stem Cells International. 2018.
96. Kim WS, Park BS, Sung JH. The wound-healing and antioxidant effects of adipose-derived stem cells. Expert Opinion on Biological Therapy. 2009; 9: 879-887.
97. Jiang YH, Kuo YC, Jhang JF, Lee CL, Hsu YH, Ho HC, et al. Repeated intravesical injections of platelet-rich plasma improve symptoms and alter urinary functional proteins in patients with refractory interstitial cystitis. Sci Rep. 2020; 10.
98. Jhang JF, Lin TY, Kuo HC. Editorial Comment: Intravesical injections of platelet-rich plasma is effective and safe in treatment of interstitial cystitis refractory to conventional treatment-A prospective clinical trial. Int Braz J Urol. 2021; 47: 703-709.
99. Lee YK, Jiang YH, Jhang JF, Ho HC, Kuo HC. Changes in the ultrastructure of the bladder urothelium in patients with interstitial cystitis after intravesical injections of platelet-rich plasma. Biomedicines. 2022; 10: 1182.
100. Trifunovic S, Stevanovic I, Milosevic A, Ristic N, Janjic M, Bjelobaba I, et al. The Function of the Hypothalamic–Pituitary–Adrenal axis during experimental autoimmune encephalomyelitis: Involvement of Oxidative Stress Mediators. Front Neurosci. 2021; 15.