Urological Research最新文献

The objective of this study is to understand pathogenesis of melamine-related kidney stone formation. We investigated the characterization of renal tubular cell under exposure to a mixture of melamine and cyanuric acid in vivo. Male Sprague-Dawley rats were separated into two experimental groups. Treatment group was administered daily with a standard commercial diet mixing with melamine and cyanuric acid, and control group was given a normal diet. Rat kidney specimens were stained with hematoxylin/eosin and the crystals were examined using a polarizing microscope. Renal tubular epithelial cells were observed by transmission electron microscopy. Semiquantitative RT-PCR assay was performed to determine monocyte chemoattractant protein-1 (MCP-1) mRNA expression, a protein in response to various proinflammatory stimuli. Apoptotic cells were examined by TUNEL assay. Melamine-associated crystals formed in glomerulus and wide renal tubule segment including proximal convoluted renal tubules, distal convoluted renal tubules, the limb loops of Henle and medullary collecting ducts in the cortex and medulla. Light microscopy results showed that the crystals lead to tubular lumen dilatation and tubular epithelial cell necrosis. It was observed that nucleus of renal tubular epithelial cells became irregular outlines and condensed, lysosomal-related structures increased, and integrity of renal tubule was deficient under electron microscopy. Apoptotic cells were noted widely in cortex and medulla. MCP-1 mRNA expression was significantly increased in the melamine and cyanuric acid-administrated group. Renal tubular epithelial cell injury, apoptosis and inflammation are involved in melamine-related kidney stone formation. Our findings are important for understanding pathogenesis of melamine-related kidney stone formation and estimating its clinical prognosis.

Urinary stones consist of two phases-an inorganic (mineral) phase and an organic (matrix) phase. Studies on the organic components of kidney stones have been undertaken later than those on the inorganic components. After osteopontin was identified as one of the matrix components, the biomolecular mechanism of urinary stone formation became clearer. It also triggered the development of new preventive treatments. Osteopontin expression is sporadically observed in normal distal tubular cells and is markedly increased in stone-forming kidneys. Calcium oxalate crystals adhering to renal tubular cells are incorporated into cells by the involvement of osteopontin. Stimulation of crystal-cell adhesion impairs the opening of mitochondrial permeability transition pores (mPTP) in tubular cells and produces oxidative stress, apoptosis, and osteopontin expression. Macrophages phagocytose and digest a small amount of crystals, but many crystals aggregate into a mass containing osteopontin and epithelial cell debris and are excreted into the renal tubular lumen, becoming nuclei of urinary stones. This biomolecular mechanism is similar to atherosclerotic calcification. Based on these findings, new preventive treatments have been developed. Dietary control such as low-cholesterol intake and the ingestion of antioxidative foods and vegetables have successfully reduced the 5-year recurrence rate. Osteopontin antibodies and cyclosporine A, which blocks the opening of mPTP, have markedly inhibited the expression of osteopontin and urinary stone formation in animal models.

Flos carthami (FC), also known as Carthamus tinctorius, is a traditional Chinese herbal plant that has been prescribed since centuries for treating various symptoms related to blood circulation improvement. This study aimed to investigate the effects of FC on calcium oxalate (CaOx) formation in ethylene glycol (EG)-fed rats. A total of 50 male Sprague-Dawley rats were divided into the following 6 groups: group 1, as the normal control (n = 5); group 2 received gastric gavages of starch and 0.75% EG (placebo, n = 5) as a stone inducer; group 3 (n = 10) received EG and potassium citrate as positive controls; group 4 (n = 10) received 0.75% EG and 300 mg/day FC; group 5 (n = 10) was treated with EG and 600 mg/day FC; group 6 (n = 10) received with EG and 1,200 mg/day FC. For all experimental animals, 24-h urine and blood samples were analyzed at the beginning and end of the experiment. Kidney tissue was histopathologically examined using a polarized light microscope, and crystal deposits were evaluated by a semi-quantitative scoring method; these scores were significantly lower in the FC groups (600 and 1,200 mg/day) than in the placebo group. Thus, FC administration appeared to inhibit the deposition of CaOx crystal EG-fed rats. We, therefore, consider that FC may be effective for preventing stone disease, albeit with certain side effects, such as a bleeding tendency. Further clinical trials are needed for evaluating its benefits and possible side effects.

The aim of this study was to evaluate the outcome of staged single-tract minimally invasive percutaneous nephrolithotomy (MPCNL) and flexible ureteroscopy as a minimally invasive option in the treatment of staghorn stone in patients with a solitary kidney. A total of 24 patients with staghorn stone in a solitary kidney were treated with single-tract MPCNL and flexible ureteroscopy by a single surgeon. All the patients underwent single-tract MPCNL through a 20 F tract and had most of the intrarenal calculi removed at the first stage. The second stage of retrograde flexible ureteroscopy was performed 3-5 days later, after the drainage was cleared. The preoperative patient, characteristics, stone size, operative time, renal functional status and postoperative outcomes were then evaluated. Sixteen patients were partial staghorn (66.7 %), and other eight were complete staghorn (33.3 %). The overall stone-free rate was 83.3 % after the second-stage procedures, and only four patients had significant residue. The hemoglobin drop ranged from 1.1 to 3.7 g/dl, and three patients required blood transfusion. The mean serum creatinine value was 1.7 ± 0.5 mg/dl before surgery and 1.3 ± 0.4 mg/dl at the end of the follow-up period with statistical significance (P < 0.05). None of the patients had increased serum creatinine, and needed dialysis at the end of the follow-up period. Staged single-tract MPCNL and flexible ureteroscopy are safe and effective for the management of staghorn stone in patients with a solitary kidney and even in patients with impaired renal functions.

The last decade flexible ureteroscopy has progressed from an awkward diagnostic procedure with limited visualization to a precise surgical intervention allowing access to the entire collecting system. In this review, we present the current status and future perspectives of the ureterorenoscopic management of urolithiasis and non-stone-related upper tract pathologies.

The objective of this study is to analyze the alterations in bone mineral density and bone and calcium-phosphorus metabolism in patients with calcium nephrolithiasis. We designed a study with 182 patients who were distributed among three groups: group O, 56 patients without nephrolithiasis; group A, 67 patients with calcium nephrolithiasis and mild lithogenic activity; and group B, 59 patients with calcium nephrolithiasis and severe lithogenic activity. Metabolic parameters of blood and urine that were related to calcium-phosphorous and bone metabolism and bone densitometry were assessed in all patients. A comparative study was performed on the variables of bone and calcium-phosphorus metabolism and bone densitometry as well as the presence or absence of osteopenia/osteoporosis. The patients in group B had a greater loss of bone mineral density, measured by the T-score, than the patients in groups O and A. Moreover, the proportion of patients in group B with osteopenia/osteoporosis was statistically significantly higher than the proportion of patients in groups O and A. We observed higher values of calciuria, fasting calcium/creatinine ratio, and 24-h calcium/creatinine among the patients in group B compared to the other two groups. Calciuria, citraturia, and fasting calcium/creatinine were independent factors that showed a relationship with severe lithogenic activity compared to the control group, and β-crosslaps is an independent factor that has a relationship with severe lithogenic activity as compared to mild lithogenic activity. Patients with calcium lithiasis and severe lithogenic activity have a greater loss in bone mineral density and therefore a greater risk of osteopenia/osteoporosis.

Holarrhena antidysenterica has a traditional use in the treatment of urolithiasis, therefore, its crude extract has been investigated for possible antiurolithic effect. The crude aqueous-methanolic extract of Holarrhena antidysenterica (Ha.Cr) was studied using the in vitro and in vivo methods. In the in vitro experiments, Ha.Cr demonstrated a concentration-dependent (0.25-4 mg/ml) inhibitory effect on the slope of aggregation. It decreased the size of crystals and transformed the calcium oxalate monohydrate (COM) to calcium oxalate dehydrate (COD) crystals, in calcium oxalate metastable solutions. It also showed concentration-dependent antioxidant effect against 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals and lipid peroxidation induced in rat kidney tissue homogenate. Ha.Cr (0.3 mg/ml) reduced (p < 0.05) the cell toxicity and LDH release in renal epithelial cells (MDCK) exposed to oxalate (0.5 mM) and COM (66 μg/cm(2)) crystals. In male Wistar rats, receiving 0.75 % ethylene glycol (EG) for 21 days along with 1 % ammonium chloride (AC) in drinking water, Ha.Cr treatment (30-100 mg/kg) prevented the toxic changes caused by lithogenic agents; EG and AC, like loss of body weight, polyurea, oxaluria, raised serum urea and creatinine levels and crystal deposition in kidneys compared to their respective controls. These data indicate that Holarrhena antidysenterica possesses antiurolithic activity, possibly mediated through the inhibition of CaOx crystal aggregation, antioxidant and renal epithelial cell protective activities and may provide base for designing future studies to establish its efficacy and safety for clinical use.

We reviewed our 6 years of experience with endoscopic holmium: yttrium aluminum garnet (YAG) laser lithotripsy for treatment of urinary stones in different locations in 111 children. A retrospective review was performed on endoscopic holmium: YAG laser lithotripsy procedures performed to treat stones in children between March 2006 and March 2012. In total, 120 laser lithotripsy procedures were performed to treat 131 stones in 111 children (80 males and 31 females; age range, 11 months to 16 years; median age, 6 years). Stones were located in the kidney in 48 cases (36.7 %), ureter in 52 (39.7 %), bladder in 21 (16.0 %), and urethra in 10 (7.6 %). Stone size ranged from 4 to 30 mm (mean, 12.8 mm), and anesthesia duration was 10-170 min (mean, 56 min). Forty-four ureters required balloon dilation, and 61 double J stents were inserted. Follow-up ranged from 3 to 75 months (mean, 35 months). Complete stone clearance was achieved at the end of the procedure in 102 (91.9 %) patients (age < 7 years, 93.3 % vs. age ≥ 7 years, 90.2 %; p > 0.05). The success rate was 81.3 % for kidney stones (<10 mm, 90.9 % vs. ≥ 10 mm, 78.4 %; p > 0.05) and 100 % for the ureter, bladder, and urethral stones. Overall success rate with extracorporeal shockwave lithotripsy was 100 %. No major complications were encountered during or after the procedures. These results confirm the effectiveness and safety of holmium laser lithotripsy for treating all urinary stone locations in children of all ages.