Functional recovery of urethra by plasmid DNA-loaded injectable agent for the treatment of urinary incontinence

Use of bioactive extracellular matrix fragments as a urethral bulking agent to treat stress urinary incontinence

Injection of urethral bulking agents is a low-risk, minimally invasive surgical procedure to treat stress urinary incontinence (SUI). In this study, we developed a promising injectable bulking agent comprising extracellular matrix fragments of adipose-derived stem cell sheets (ADSC ECM) and investigated its effectiveness in urethral bulking therapy. The structural integrity and proteins of ADSC sheet ECM were well retained in decellularized ADSC ECM fragments. To locate transplanted ADSC ECM fragments, they were labeled with ultrasmall super-paramagnetic iron oxide nanoparticles, which enabled in vivo monitoring after implantation in a SUI rat model for up to 4 weeks. When ADSC ECM fragments were injected into the rat urethra, they became fully integrated with the surrounding tissue within 1 week. Four weeks after transplantation, host cells had regenerated within the ADSC ECM fragment injection area. Moreover, new smooth muscle tissue had formed around the ADSC ECM fragments, as confirmed by positive staining of myosin. These results indicate that injection of ECM fragments may be a promising minimally invasive approach for treating SUI.

Biomaterial Scaffolds for Reproductive Tissue Engineering

The reproductive system usually involves gamete producing gonads, a series of specialized ducts, accessory glands and the external genitalia. Despite there are many traditional methods such as hormonal and surgical approaches, at present no effective treatments exist to help patients suffering from serious diseases of reproductive system, including congenital and acquired abnormalities, malignant tumor, traumatic, infectious etiologies, inflammation and iatrogenic injuries. Tissue engineering holds promise for reproductive medicine through the development of biological alternative. Till now, a diverse range of biomaterials have been utilized as suitable substrates to match both the mechanical and biological context of reproductive tissues. The current review will focus mainly on the applications of biomaterial scaffolds and their major achievements in each region of reproductive systems.

Smart doxorubicin nanoparticles with high drug payload for enhanced chemotherapy against drug resistance and cancer diagnosis

Considering the obvious advantages in efficacy and price, doxorubicin (DOX) has been widely used for a range of cancers, which is usually encapsulated in various nanocarriers for drug delivery. Although effective, in most nanocarrier-based delivery systems, the drug loading capacity of DOX is rather low; this can lead to undesired systemic toxicity and excretion concern. Herein, we report for the first time the usage of pure doxorubicin nanoparticles (DOX NPs) without addition of any carriers for enhanced chemotherapy against drug-resistance. The drug payload reaches as high as 90.47%, which largely surpassed those in previous reports. These PEG stabilized DOX NPs exhibit good biocompatibility and stability, long blood circulation time, fast release in an acidic environment and high accumulation in tumors. Compared with free DOX, DOX NPs display a dramatically enhanced anticancer therapeutic efficacy in the inhibition of cell and tumor growth. Moreover, they can also be readily incorporated with other anticancer drugs for synergistic chemotherapy to overcome the drug resistance of cancers. The fluorescence properties of DOX also endow these NPs with imaging capabilities, thus making it a multifunctional system for diagnosis and treatment. This work demonstrates great potential of DOX NPs for cancer diagnosis, therapy and overcoming drug tolerance.

Dual growth factor-immobilized microspheres for tissue reinnervation: in vitro and preliminary in vivo studies

Growth factors (GFs) (basic fibroblast growth factor (bFGF) and/or nerve growth factor (NGF))-immobilized polycaprolactone (PCL)/Pluronic F127 microspheres were prepared using an isolated particulate-melting method and the sequential binding of heparin and GFs onto the microspheres. The GFs immobilized on the microspheres were released in a sustained manner over 28 days, regardless of GF type. From the in vitro culture of muscle-derived stem cells, it was observed that the NGF-immobilized microspheres induced more neurogenic differentiation than the bFGF-immobilized microspheres, as evidenced by a quantitative real-time polymerase chain reaction using specific neurogenic markers (Nestin, GFAP, β-tubulin, and MAP2) and Western blot (Nestin and β-tubulin) analyses. The dual bFGF/NGF-immobilized microspheres showed better neurogenic differentiation than the microspheres immobilized with single bFGF or NGF. From the preliminary animal study, the dual bFGF/NGF-immobilized microsphere group also showed effective nerve regeneration, as evaluated by immunocytochemistry using a marker - β-tubulin. The dual bFGF/NGF-immobilized PCL/Pluronic F127 microspheres may be a promising candidate for nerve regeneration in certain target tissues (i.e. muscles) leading to sufficient reinnervation.

Dual growth factor-loaded in situ gel-forming bulking agent: passive and bioactive effects for the treatment of urinary incontinence

Stress urinary incontinence (SUI) is one of the major medical problems for adult females and has a devastating effect on their quality of life. The major cause of the development of the SUI is dysfunction of the urethral supporting tissues as a result of aging and childbirth. In this study, in situ gel-forming bulking agent loaded with dual growth factors, nerve growth factor (NGF) and basic fibroblast growth factor (bFGF), was fabricated. The bulking agent consisted of three components; (i) polycaprolactone (PCL) beads, (ii) bFGF-loaded nanogels, and (iii) NGF-loaded in situ gel forming solution. The bulking agent can provide an initial passive bulking effect (from the PCL beads) and regenerate malfunctioning tissues around the urethra (from the sequential and continuous release of growth factors from the hydrogel) for the effective treatment of SUI. The PCL beads were located stably at the applied urethra site (urinary incontinent SD rat) without migration to provide a passive bulking effect. The sequential release of the growth factors (NGF within a week and bFGF for more than 4 weeks) from the bulking agent provided regeneration of damaged nerve and smooth muscle, and thus enhanced biological function around the urethra. From the findings, we suggest that dual growth factor (NGF and bFGF)-loaded in situ gel-forming bulking agent may be a promising injectable bioactive system for the treatment for SUI.

Effect of porous polycaprolactone beads on bone regeneration: preliminary in vitro and in vivo studies

Background

For the effective bone regeneration with appropriate pathological/physiological properties, a variety of bone fillers have been adapted as a therapeutic treatment. However, the development of ideal bone fillers is still remained as a big challenge in clinical practice. The main aims of this study are i) fabrication of a highly porous PCL beads; and ii) the estimation of the potential use of the porous PCL beads as a bone filler through preliminary animal study.

Results

The porous PCL beads with size range of 53 ~ 600 μm (425 ~ 500 μm dominantly) are fabricated by a spray/precipitation method using a double nozzle spray and PCL solution (in tetraglycol). The PCL beads show highly porous inner pore structure and the pores are interconnected with outer surface pores. For the preliminary animal study, we recognize that the porous PCL bead can induce the new bone formation from the outer surface of bone defect toward the bone marrow cavity through the bead matrix.

Conclusions

From the preliminary results, we can suggest that the highly porous PCL beads may be a promising candidate as a bone filler (scaffolding matrix) for the effective bone regeneration.

New horizons: urinary incontinence in older people

Urinary incontinence is a common complaint in older people, and is associated with significant impact on the individual, their carers and the wider healthcare system. As the numbers of frail elderly people increase, so will the burden of incontinence. This review examines recent developments in research into the aetiology, physiology, pathology and treatment of urinary incontinence and lower urinary tract symptoms in older people, and explores potential future developments which might reduce or ameliorate both urinary incontinence and its effects on frail older people. These include increasing understanding of the importance of central control of continence, the role of the urothelium as a sensory organ, novel targets for pharmacological treatments and surgical and invasive interventions.

Tissue engineered bulking agent with adipose-derived stem cells and silk fibroin microspheres for the treatment of intrinsic urethral sphincter deficiency

In this study we developed a tissue engineered bulking agent that consisted of adipose-derived stem cells (ADSCs) and silk fibroin microspheres to treat stress urinary incontinence caused by severe intrinsic sphincter deficiency (ISD). ISD models were established by completely transection of the bilateral pudendal nerve (PNT) and confirmed by the decreased leak-point pressure (LPP) and increased lumen area of urethra. Injection of silk fibroin microspheres could recover LPP and lumen area at 4 weeks but its efficacy disappears at 8, 12 weeks. Moreover, it was exciting to find that tissue engineered bulking agent brought long-term efficacy (at 4, 8, 12 weeks post-injection) on the recovery of LPP and lumen area. Concomitantly with the function, tissue engineered bulking agent treated group also improved the urethral sphincter structure as exhibited by better tissue regeneration. The findings showed that silk fibroin microspheres alone could work effectively in short-term, while tissue engineered bulking agent that combined silk fibroin microspheres with ADSCs exhibited promising long-term efficacy. This study developed a new strategy of tissue engineered bulking agent for future ISD therapy.

Regenerative medicine based applications to combat stress urinary incontinence

Stress urinary incontinence (SUI), as an isolated symptom, is not a life threatening condition. However, the fear of unexpected urine leakage contributes to a significant decline in quality of life parameters for afflicted patients. Compared to other forms of incontinence, SUI cannot be easily treated with pharmacotherapy since it is inherently an anatomic problem. Treatment options include the use of bio-injectable materials to enhance closing pressures, and the placement of slings to bolster fascial support to the urethra. However, histologic findings of degeneration in the incontinent urethral sphincter invite the use of tissues engineering strategies to regenerate structures that aid in promoting continence. In this review, we will assess the role of stem cells in restoring multiple anatomic and physiological aspects of the sphincter. In particular, mesenchymal stem cells and CD34⁺ cells have shown great promise to differentiate into muscular and vascular components, respectively. Evidence supporting the use of cytokines and growth factors such as hypoxia-inducible factor 1-alpha, vascular endothelial growth factor, basic fibroblast growth factor, hepatocyte growth factor and insulin-like growth factor further enhance the viability and direction of differentiation. Bridging the benefits of stem cells and growth factors involves the use of synthetic scaffolds like poly (1,8-octanediol-co-citrate) (POC) thin films. POC scaffolds are synthetic, elastomeric polymers that serve as substrates for cell growth, and upon degradation, release growth factors to the microenvironment in a controlled, predictable fashion. The combination of cellular, cytokine and scaffold elements aims to address the pathologic deficits to urinary incontinence, with a goal to improve patient symptoms and overall quality of life.