Jae Heon Kim

Stem cell therapy in bladder dysfunction: where are we? And where do we have to go?

To date, stem cell therapy for the bladder has been conducted mainly on an experimental basis in the areas of bladder dysfunction. The therapeutic efficacy of stem cells was originally thought to be derived from their ability to differentiate into various cell types. Studies about stem cell therapy for bladder dysfunction have been limited to an experimental basis and have been less focused than bladder regeneration. Bladder dysfunction was listed in MESH as “urinary bladder neck obstruction”, “urinary bladder, overactive”, and “urinary bladder, neurogenic”. Using those keywords, several articles were searched and studied. The bladder dysfunction model includes bladder outlet obstruction, cryoinjured, diabetes, ischemia, and spinal cord injury. Adipose derived stem cells (ADSCs), bone marrow stem cells (BMSCs), and skeletal muscle derived stem cells (SkMSCs) are used for transplantation to treat bladder dysfunction. The main mechanisms of stem cells to reconstitute or restore bladder dysfunction are migration, differentiation, and paracrine effects. The aim of this study is to review the stem cell therapy for bladder dysfunction and to provide the status of stem cell therapy for bladder dysfunction.

Treatment of Bladder Dysfunction Using Stem Cell or Tissue Engineering Technique

Tissue engineering and stem cell transplantation are two important options that may help overcome limitations in the current treatment strategy for bladder dysfunction. Stem cell therapy holds great promise for treating pathophysiology, as well as for urological tissue engineering and regeneration. To date, stem cell therapy in urology has mainly focused on oncology and erectile dysfunction. The therapeutic potency of stem cells (SCs) was originally thought to derive from their ability to differentiate into various cell types including smooth muscle. The main mechanisms of SCs in reconstituting or restoring bladder function are migration, differentiation, and paracrine effects. Nowadays, paracrine effects of stem cells are thought to be more prominent because of their stimulating effects on stem cells and adjacent cells. Studies of stem cell therapy for bladder dysfunction have been limited to experimental models and have been less focused on tissue engineering for bladder regeneration. Bladder outlet obstruction is a representative model. Adipose-derived stem cells, bone marrow stem cells (BMSCs), and skeletal muscle-derived stem cells or muscle precursor cells are used for transplantation to treat bladder dysfunction. The aim of this study is to review stem cell therapy and updated tissue regeneration as treatments for bladder dysfunction and to provide the current status of stem cell therapy and tissue engineering for bladder dysfunction including its mechanisms and limitations.

Predicting the Histology of Small Renal Masses Using Preoperative Dynamic Contrast-enhanced Magnetic Resonance Imaging

OBJECTIVE To study whether magnetic resonance imaging can predict the histologic type of small renal cell carcinoma. METHODS Dynamic contrast-enhanced magnetic resonance imaging was performed in 63 patients with computed tomography- or ultrasonography-suspected small (≤ 4 cm) renal cell carcinoma from February 2008 to February 2010. Percentage signal intensity change, tumor-to-cortex enhancement index during precontrast phase, corticomedullary phase, and nephrogenic phase were investigated. RESULTS Among the 60 patients, 42 were proven to have clear cell renal cell carcinoma and 18 patients were proven to have non-clear cell renal cell carcinoma (10 patients with papillary renal cell carcinoma, 8 patients with chromophobe renal cell carcinoma). The percentage signal intensity change in the clear cell type was higher only in the corticomedullary phase (P = .002). The tumor-to-cortex enhancement index in the clear cell type was higher in the corticomedullary and nephrogenic phases (P = .007 and P = .041, respectively). The most valuable marker was percentage signal intensity change in the corticomedullary phase (area under the receiver operating characteristic curve 0.85). The cut-off value of percentage signal intensity change in the corticomedullary phase was 173%, and the sensitivity and specificity were 81% and 87.5%, respectively. CONCLUSION Dynamic contrast-enhanced magnetic resonance imaging could be useful for discriminating the clear cell type from non-clear cell type in small renal cell carcinoma with high sensitivity and specificity.

Efficacy and Safety of Prostatic Arterial Embolization: Systematic Review with Meta-Analysis and Meta-Regression

Purpose: This study attempted to overcome the limitations of previous systematic reviews to determine the overall treatment efficacy and safety of prostatic arterial embolization compared with standard therapy. Materials and Methods: Meta‐analyses were done of randomized, controlled and single group trials. Meta‐regression analysis of the moderator effect was performed with single group analysis. The outcomes measured were mean changes in I‐PSS (International Prostate Symptom Score), quality of life, maximal urinary flow rate, prostate volume, post‐void residual volume and prostate specific antigen. Adverse events were compared as proportional differences between the embolization group and groups receiving other therapies in comparative studies. Results: A total of 16 studies met our selection criteria and were included in the meta‐analysis. Three studies were comparative and included a total of 297 subjects, including 149 in the experimental groups and 148 in the control groups. The other 13 studies were noncomparative and included a total of 750 experimental subjects. Pooled overall standardized mean differences for embolization in I‐PSS, maximal urinary flow rate and prostate volume were significantly impaired in the experimental vs control groups. Overall weighted mean differences for all outcomes except prostate specific antigen were significantly improved from baseline by embolization treatment in noncomparative studies. Sensitivity analysis of study duration showed that all outcome measurements did not differ before vs after 6 months. Conclusions: Although there is growing evidence of the efficacy and safety of prostatic arterial embolization for benign prostatic hyperplasia, this systematic review using meta‐analysis and meta‐regression showed that prostatic arterial embolization should still be considered an experimental treatment modality.

Laparoscopic transvesical excision and reconstruction in the management of mid-urethral tape mesh erosion and stones around the bladder neck: initial experiences

Study Type – Prevalence (prospective cohort)

Primary Renal Hydatid Cyst: Mis-Interpretation as a Renal Malignancy

Primary renal echinococcosis, a rare disease involving the kidney, accounts for 2-3% of human echinococcosis. A 64-year-old female patient from Uzbekistan presented with complaints of left flank pain. A CT scan revealed a cystic mass in the upper to midpole of the left kidney. We regarded this lesion as a renal malignancy and hand-assisted laparoscopic radical nephrectomy was performed to remove the renal mass. The mass consisted of a large unilocular cyst and multiple smaller cysts without any grossly visible renal tissue. The final pathologic diagnosis was a renal hydatid cyst. For patients from endemic areas, hydatid cyst should be included in the differential diagnosis. Here, we present a case of renal hydatid cyst in a female patient who relocated from Uzbekistan to Korea.

Korean clinical practice guideline for benign prostatic hyperplasia.

In 2014, the Korean Urological Association organized the Benign Prostatic Hyperplasia Guideline Developing Committee composed of experts in the field of benign prostatic hyperplasia (BPH) with the participation of the Korean Academy of Family Medicine and the Korean Continence Society to develop a Korean clinical practice guideline for BPH. The purpose of this clinical practice guideline is to provide current and comprehensive recommendations for the evaluation and treatment of BPH. The committee developed the guideline mainly by adapting existing guidelines and partially by using the de novo method. A comprehensive literature review was carried out primarily from 2009 to 2013 by using medical search engines including data from Korea. Based on the published evidence, recommendations were synthesized, and the level of evidence of the recommendations was determined by using methods adapted from the 2011 Oxford Centre for Evidence-Based Medicine. Meta-analysis was done for one key question and four recommendations. A draft guideline was reviewed by expert peer reviewers and discussed at an expert consensus meeting until final agreement was achieved. This evidence-based guideline for BPH provides recommendations to primary practitioners and urologists for the diagnosis and treatment of BPH in men older than 40 years.

Current status of penile rehabilitation after radical prostatectomy

Although disease-free survival remains the primary goal of prostate cancer treatment, erectile dysfunction (ED) remains a common complication that affects the quality of life. Even though several preventive and therapeutic strategies are available for ED after radical prostatectomy (RP), no specific recommendations have been made on the optimal rehabilitation or treatment strategy. Several treatment options are available, including phosphodiesterase-5 inhibitors, vacuum erection devices, intracavernosal or intraurethral prostaglandin injections, and penile prostheses. Urologists must consider more effective ways to establish optimal treatments for ED after RP. ED is an important issue among patients with prostate cancer, and many patients hope for early ED recovery after surgery. This review highlights the currently available treatment options for ED after RP and discusses the limitations of each.

Cytosine deaminase-expressing human neural stem cells inhibit tumor growth in prostate cancer-bearing mice

Prostate cancer is the most common malignancy among men. Prostate cancer-related deaths are largely attributable to the development of hormone resistance in the tumor. No effective chemotherapy has yet been developed for advanced prostate cancer. It is desirable if a drug can be delivered directly and specifically to prostate cancer cells. Stem cells have selective migration ability toward cancer cells and therapeutic genes can be easily transduced into stem cells. In one form of gene therapy for cancer, the stem cells carry a gene encoding an enzyme that transforms an inert prodrug into a toxic product. Cytosine deaminase (CD) transforms the pro-drug 5-fluorocytosine into highly cytotoxic 5-fluorouracil (5-FU). The migration of the genetically modified stem cells was monitored by molecular magnetic resonance imaging, after labeling the stem cells with fluorescent magnetic nanoparticles (MNPs). Human neural stem cells encoding CD (HB1.F3.CD) were prepared and labeled with MNP. In tumor-bearing C57B mice, systemically transplanted HB1.F3.CD stem cells migrated toward the tumor and in combination with prodrug 5-FC, the volume of tumor implant was significantly reduced. These findings may contribute to development of a new selective chemotherapeutic strategy against prostate cancer.

Is Tamsulosin 0.2 mg Effective and Safe as a First-Line Treatment Compared with Other Alpha Blockers?: A Meta-Analysis and a Moderator Focused Study

Purpose Tamsulosin 0.2 mg is used widely in Asian people, but the low dose has been studied less than tamsulosin 0.4 mg or other alpha blockers of standard dose. This study investigated the efficacy and safety of tamsulosin 0.2 mg by a meta-analysis and meta-regression. Materials and Methods We conducted a meta-analysis of efficacy of tamsulosin 0.2 mg using International Prostate Symptom Score (IPSS), maximal urinary flow rate (Qmax), post-voided residual volume (PVR), and quality of life (QoL). Safety was analyzed using adverse events. Relevant studies were searched using MEDLINE, EMBASE, and Cochrane library from January 1980 to June 2013. Results Ten studies were included with a total sample size of 1418 subjects [722 tamsulosin 0.2 mg group and 696 other alpha-blockers (terazosin, doxazosin, naftopidil, silodosin) group]. Study duration ranged from 4 to 24 weeks. The pooled overall standardized mean differences (SMD) in the mean change of IPSS from baseline for the tamsulosin group versus the control group was 0.02 [95% confidence interval (CI); -0.20, 0.25]. The pooled overall SMD in the mean change of QoL from baseline for the tamsulosin group versus the control group was 0.16 (95% CI; -0.16, 0.48). The regression analysis with the continuous variables (number of patients, study duration) revealed no significance in all outcomes as IPSS, QoL, and Qmax. Conclusion This study clarifies that tamsulosin 0.2 mg has similar efficacy and fewer adverse events compared with other alpha-blockers as an initial treatment strategy for men with lower urinary tract symptoms.