A Systematic Review of the Evidence of Hematopoietic Stem Cell Differentiation to Fibroblasts

Fibroblasts have an important role in the maintenance of the extracellular matrix of connective tissues by producing and remodelling extracellular matrix proteins. They are indispensable for physiological processes, and as such also associate with many pathological conditions. In recent years, a number of studies have identified donor-derived fibroblasts in various tissues of bone marrow transplant recipients, while others could not replicate these findings. In this systematic review, we provide an overview of the current literature regarding the differentiation of hematopoietic stem cells into fibroblasts in various tissues. PubMed, Embase, and Web of Science (Core Collection) were systematically searched for original articles concerning fibroblast origin after hematopoietic stem cell transplantation in collaboration with a medical information specialist. Our search found 5421 studies, of which 151 were analysed for full-text analysis by two authors independently, resulting in the inclusion of 104 studies. Only studies in animals and humans, in which at least one marker was used for fibroblast identification, were included. The results were described per organ of fibroblast engraftment. We show that nearly all mouse and human organs show evidence of fibroblasts of hematopoietic stem cell transfer origin. Despite significant heterogeneity in the included studies, most demonstrate a significant presence of fibroblasts of hematopoietic lineage in non-hematopoietic tissues. This presence appears to increase after the occurrence of tissue damage.

Considerations for the clinical use of stem cells in genitourinary regenerative medicine

The genitourinary tract can be affected by several pathologies which require repair or replacement to recover biological functions. Current therapeutic strategies are challenged by a growing shortage of adequate tissues. Therefore, new options must be considered for the treatment of patients, with the use of stem cells (SCs) being attractive. Two different strategies can be derived from stem cell use: Cell therapy and tissue therapy, mainly through tissue engineering. The recent advances using these approaches are described in this review, with a focus on stromal/mesenchymal cells found in adipose tissue. Indeed, the accessibility, high yield at harvest as well as anti-fibrotic, immunomodulatory and proangiogenic properties make adipose-derived stromal/SCs promising alternatives to the therapies currently offered to patients. Finally, an innovative technique allowing tissue reconstruction without exogenous material, the self-assembly approach, will be presented. Despite advances, more studies are needed to translate such approaches from the bench to clinics in urology. For the 21^st century, cell and tissue therapies based on SCs are certainly the future of genitourinary regenerative medicine.

Stem cell therapy for chronic obstructive pulmonary disease

ABSTRACT

Chronic obstructive pulmonary disease (COPD), characterized by persistent and not fully reversible airflow restrictions, is currently one of the most widespread chronic lung diseases in the world. The most common symptoms of COPD are cough, expectoration, and exertional dyspnea. Although various strategies have been developed during the last few decades, current medical treatment for COPD only focuses on the relief of symptoms, and the reversal of lung function deterioration and improvement in patient's quality of life are very limited. Consequently, development of novel effective therapeutic strategies for COPD is urgently needed. Stem cells were known to differentiate into a variety of cell types and used to regenerate lung parenchyma and airway structures. Stem cell therapy is a promising therapeutic strategy that has the potential to restore the lung function and improve the quality of life in patients with COPD. This review summarizes the current state of knowledge regarding the clinical research on the treatment of COPD with mesenchymal stem cells (MSCs) and aims to update the understanding of the role of MSCs in COPD treatment, which may be helpful for developing effective therapeutic strategies in clinical settings.

Current and Future Directions of Stem Cell Therapy for Bladder Dysfunction

Stem cells are capable of self-renewal and differentiation into a range of cell types and promote the release of chemokines and progenitor cells necessary for tissue regeneration. Mesenchymal stem cells are multipotent progenitor cells with enhanced proliferation and differentiation capabilities and less tumorigenicity than conventional adult stem cells; these cells are also easier to acquire. Bladder dysfunction is often chronic in nature with limited treatment modalities due to its undetermined pathophysiology. Most treatments focus on symptom alleviation rather than pathognomonic changes repair. The potential of stem cell therapy for bladder dysfunction has been reported in preclinical models for stress urinary incontinence, overactive bladder, detrusor underactivity, and interstitial cystitis/bladder pain syndrome. Despite these findings, however, stem cell therapy is not yet available for clinical use. Only one pilot study on detrusor underactivity and a handful of clinical trials on stress urinary incontinence have reported the effects of stem cell treatment. This limitation may be due to stem cell function loss following ex vivo expansion, poor in vivo engraftment or survival after transplantation, or a lack of understanding of the precise mechanisms of action underlying therapeutic outcomes and in vivo behavior of stem cells administered to target organs. Efficacy comparisons with existing treatment modalities are also needed for the successful clinical application of stem cell therapies. This review describes the current status of stem cell research on treating bladder dysfunction and suggests future directions to facilitate clinical applications of this promising treatment modality, particularly for bladder dysfunction.

Stem cell antigen/Ly6a protects against bladder fibrosis in mice

We have defined a population of stem cell antigen (Sca)-1⁺/CD34⁺/lin^- mesenchymal stem cells in the mouse urinary bladder. These cells are reduced after partial bladder outlet obstruction (PO). To test the role of Sca-1 expressed by these cells, we analyzed bladders from Sca-1 knockout (KO) mice in both uninjured male mice and male mice subjected to PO. We found that loss of Sca-1 alone had little effect on bladder development or function but reduced the total number of mesenchymal stem cells by 30%. After PO, bladders from Sca-1-null KO male mice were larger, with more collagen and less muscle, than obstructed wild-type mice. Steady-state levels of caldesmon were significantly reduced and levels of fibroblast-specific protein 1 were significantly increased in Sca-1 KO mice compared with wild-type mice after PO. In investigating the effects of PO on cell proliferation, we found that loss of Sca-1 changed the timing of cell division in CD34⁺/lin^-, collagen-producing, and smooth muscle cells. PO in combination with loss of Sca-1 drastically reduced the ability of CD34⁺/lin^- cells to form colonies in vitro. Our findings therefore support the hypothesis that Sca-1 protects the bladder from fibrotic remodeling after obstruction, in part by influencing the proliferation of cells responding to the injury.

Application of the allogenic mesenchymal stem cells in the therapy of the bladder tuberculosis

Urogenital tuberculosis (TB) often leads to contraction of the bladder, a reduction of the urinary reservoir capacity, and, in the latest stage, to real microcystitis up to full obliteration. Bladder TB Stage 4 is unsuitable for conservative therapy, and cystectomy with subsequent enteroplasty is indicated. In this study, using a model of bladder TB in New Zealand rabbits, the therapeutic efficacy of the interstitial injection of autologous bone-derived mesenchymal stem cells (MSCs) combined with standard anti-TB treatment in the restoration of the bladder function was demonstrated. For analysis of the MSC distribution in tissues, the latter were labelled with superparamagnetic iron oxide nanoparticles. In vitro studies demonstrated the high intracellular incorporation of nanoparticles and the absence of cytotoxicity on MSC viability and proliferation. A single-dose administration of MSCs into the bladder mucosal layer significantly reduced the wall deformation and inflammation and hindered the development of fibrosis, which was proven by the subsequent histological assay. Confocal microscopy studies of the bladder cryosections confirmed the presence of superparamagnetic iron oxide nanoparticle-labelled MSCs in different bladder layers of the treated animals, thus indicating the role of stem cells in bladder regeneration.

Bone marrow mesenchymal stem cell therapy for voiding dysfunction

Lower urinary tract symptoms can significantly impact quality of life. Current standard treatments are not always effective and are associated with complications and side effects. The discovery of stem cells led to research into cell-based therapies for treatment of disorders of voiding dysfunction. Bone marrow mesenchymal stem cells are particularly promising given their ability to differentiate into a variety of cell types. Recent studies have investigated bone marrow stem cells to treat a number of functional voiding pathologies including bladder outlet obstruction, neurogenic bladder, and stress urinary incontinence. Experiments in tissue regeneration have also attempted to create artificial bladders and urethras. The purpose of this article is to critically review the literature regarding the use of bone marrow mesenchymal stem cells in treatment of voiding dysfunction.