The Clinical Significance of Intrarenal Reflux in Voiding Cystourethrography (VCUG)

PURPOSE: Intrarenal reflux (IRR) occurs in 3-10% of cases of total reflux and can lead to renal injury, which may eventually result in renal scarring. In this study, we evaluated the clinical importance of IRR detected by voiding cystourethrography and evaluated the relationship between IRR and renal scarring. MATERIALS AND METHODS: From January 2002 to May 2008, 50 patients who were diagnosed with vesicoureteral reflux (VUR) and showed IRR in voiding cystourethrography were enrolled. IRR was seen in 59 renal units in our enrolled patients. A 99mTc 2,3-dimercaptosuccinic acid (DMSA) renal scan was performed after VUR was detected in all cases. Nine patients were conservatively treated with prophylactic antibiotics, whereas 41 patients received an anti-reflux operation. A follow-up renal scan was performed after 3 to 6 months to check for any changes in renal scarring. RESULTS: The average patient age was 9.2 months (range, 1-42 months). Forty-nine patients were male; only one patient was female. The mean duration until surgery was 2.9 months. Generally, the IRR sites corresponded to the sites of photon defects on DMSA renal scans (76.3%). Furthermore, the photon defects on IRR sites tended to progress to renal scarring (65.2%). The rate of change in scarring was lower in the surgery group (47.1%) than in the prophylactic antibiotic group (75%). CONCLUSIONS: IRR sites and the sites of photon defects on DMSA renal scans showed a high correspondence, and these sites tended to progress to renal scarring. We suggest that VUR with IRR should be actively managed to decrease the chances of renal scarring.

Differentiation to renal tubular epithelial-like cells from bone marrow mesenchymal stem cells in vitro / 中华肾脏病杂志

Objective To investigate the differentiation of rat bone marrow mesenchymal stem cells (MSCs) to renal tubular epithelial-like cells under different conditions. Methods MSCs were obtained from rat marrow. MSCs were isolated by gradient density centrifugation and plastic adherence and then purified. Surface markers were identified with flow cytometry after amplification in vitro. The purified MSCs of the third passage were cultured respectively as follows: (1) control group: DMEM medium with fetal bovine serum(FBS). (2) all-trans retinoic acid (ATRA) group: DMEM medium with FBS, ATRA and ischemic reperfusion-injured kidney tissue homogenate. (3)combination group: DMEM medium with FBS, ATRA, ischemic reperfusion-injured kidney tissue homogenate, epidermal growth factor (EGF) and bone morphogenetic protein 7 (BMP-7). After 7 days, the MSCs were collected for alkaline phosphatase (AKP) staining, cytokeratin-18 and E-cadherin immunocytochemical analysis. Results The positive rates of the third passage MSCs in CD44, CD90 and CD29 were 97.8%±0.9%, 96.8%±1.4% and 97.6%±2.4%,respectively, but in CD11b/c and CD34 were only 13.2%±0.6% and 1.2%±0.5%. The MSCs in control group were spindle. The MSCs in ATRA group were round and elliptic. The MSCs in combination group became cobblestone-like cells after 7 days. AKP staining showed that tubular epithelial-like cells from MSCs in control group were negative, some above cells in ATRA group were positive and number of above cells increased in combination group. Compared with negative control group, the ratios of cytokeratin-18 positive cells in ATRA group and combination group were respectively increassed by 29.47%±1.08% and 47.52%±2.13% (all P<0.05), the ratios of E-cadherin positive cells in ATRA group and combination group were respectively increased by 14.88%±2.46% and 36.15%±1.13% (all P<0.05). Conclusion MSCs may differentiate by renal tubular epithelial-like cells under the induction of ischemic reperfusion-injured kidney tissue homogenate and ATRA in vitro, which are further differentiated under the combined induction of EGF and BMP-7.

High glucose induces renal epithelial-mesenchymal transition through transforming growth factor β1-Smad signaling pathway / 中华肾脏病杂志

Objective To investigate the effect of high glucose on renal tubular epithelial-mesenchymal transition,and to analyze the relationship between high glucose and transforming growth factor β1(TGF-β1)and the mechanism of renal interstitial fibrosis. Methods HKC and Smad7-overexpression HKC cells were grown in DMEM/F12 medium containing 5%～10%newborn calf serum.They were cultured for 16 h in free serum medium after 80%cells were adhered onto the surface of the flask.Afterwards,they were stimulated by high glucose(glucose concentration:25 mmol/L and 50 mmol/L).The expression of α-SMA,E-cadherin and fibronectin was detected by Western blot while the supernatant level of TGF-β1 was detected by ELISA.Cell motility and migration was evaluated using Boyden chamber motogenicity assay. Results In HKC induced by high glucose,the expression of α-SMA and fibronectin protein was highly upregulated while the expression of E-cadhefin protein was down-regulated.The expression of TGF-β1was up-regulated in a dose-dependent manner.These above-mentioned effects could be obviously inhibited by anti-TGF-β1 antibody.The protein expression of α-SMA,fibronectin and E-cadherin had no obvious change in Smad7-overexpression HKC induced by high glucose.HKC exhibited enhanced motility and invasive capacity in high glucose groups,compared to that in control group.Migrated cell counting was(12.4±3.7)and(18.6±4.4)cell/HP in 25 and 50 mmol/L glucose groups respectively. Conclusion High glucose may induce renal tubular epithelialmesenchymal transition through TGF-β1 pathway,which can be inhibited by blocking the Smad signal pathway.

High-glucose up-regulates the expression of fibronectin mediated by integrin-linked kinase in renal tubular epithelial cells / 中华肾脏病杂志

Objective To investigate the relationship between high-glucose-induced fibronectin(FN) expression and up-regulation of integrin-linked kinase(ILK) in human kidney tubular epithelial cells (HKC) and kidney of CD-1 mice. Methods Cultured human kidney tubular epithelial cells and streptozotocin (STZ)-indueed diabetic model of CD-1 mice were enrolled in this study.Western blot was used to detect the expression of FN and ILK.The kinase dead ILK plasmid (pCMV-kdlLK) were transferred to HKC. Results Four weeks after injection of STZ,CD-1 mice had higher blood glucose level as compared to the control [(20.3±2.7) mmol/L vs (6.1±1.4) mmol/L,P＜0.01].Meanwhile,expression of FN and ILK was significantly increased in diabetic mice as compared to the control (P＜0.01).There was positive correlation between the expression of FN and ILK (r=0.899,P＜0.01).High-glucose could up-regulate FN and ILK expression in cultured HKC in a time- and dose-dependent manner.Blockage of ILK activation by pCMV-kdILK abrogated high-glucose-incuced FN expression in HKC. Conclusions Highglucose can induce FN expression through up-regulating ILK expression.Blockage of ILK activation abrogates this effect.

Albumin-induced rat tubular cell apoptosis and MAPKs signal transduction / 中华肾脏病杂志

Objective To evaluate the role of albumin and the involvement of mitogenactivated protein kinases(MAPKs) in rat tubular cells apoptosis. Methods Rat tubular cells (NRK-52E) were incubated with various concentrations (10, 20, 30 mg/ml) of delipidated, endotoxin-free bovine serum albumin(BSA) for 6, 12, 18 and 24 h, respectively. The process of apoptosis was evaluated by fluorescence microscope, transmission electron microscope, scanning electron microscope, confocal laser scanning microscope (CLSM) and flow cytometry. To assess the roles of p38, and the activities of JNK and ERK in albumin-induced apoptosis, SB202190 (20 ?mol/L, p38 inhibitor), SP600125 (10 ?mol/L, JNK inhibitor) or PD98059 (20?mol/L, ERK inhibitor) were added to the NRK-52E cells separately in the presence of albumin for 24 hours. Activities of p38, JNK and ERK were assessed by Western blot analyses. Results The albumin induced tubular cell apoptosis in a doseand time-dependent manner. Albumin stimulated the expression of p38 and JNK, whereas it inhibited the expression of ERK. SB202190 and SP600125 ameliorated tubular cells apoptosis but PD980S9 treatment enhanced their apoptosis. Conclusions Albumin induces tabular cell apoptosis in a time- and dose-dependent manner in vitro, transducted through activation of p38 and JNK, and inhibition of ERK.

Expression and Distribution of Aquaporin-2, -3 and -4 in Developing Rat Kidney / 대한비뇨기과학회지

PURPOSE: The aquaporins (AQPs) are transmembrane water channel proteins. It is well known that AQP2, -3 and -4 contribute to the urinary concentration in collecting duct (CD) and also reported the presence of these three AQPs in the connecting tubule (CNT). Newborn rats are not capable of producing a concentrated urine. Rats develop the ability to concentrate urine after birth. The purpose of this study was to establish the time of the expression and the distribution of AQP2, -3 and -4 in the developing rat kidney. MATERIALS AND METHODS: Sprague-Dawley rats were used in all experiments. Kidneys were obtained from 16, 18 and 20-day-old fetuses and 1, 4, 7, 14 and 21-day-old pups and preserved and processed for immunohistochemical studies using a preembedding immunoperoxidase procedure. AQP2, -3 and -4 immunoreactivity was detected using rabbit polyclonal antibody and donkey anti-rabbit IgG. RESULTS: AQP2, -3 and -4 appeared first in 16-day-old fetuses in the CD and in 18-day-old fetuses in the CNT. Immunoreactivity for AQP2, -3 and -4 was markedly increased after birth and gradually increased during development. In CNT cells and principal cells, AQP2, -3 and -4 were not distinctly demonstrated on the apical, lateral and basal plasma membrane respectively until 21 days after birth. Distinct polarity of these AQPs both in CNTcells and principal cells were observed at 21 days after birth. CONCLUSIONS: AQP2 -3, and -4 were expressed not only in CD but also in CNT before developing of urine concentrating ability during development and it is concluded that their expression and distribution in CNT may play a role in the development of urine concentration abilities in rat kidney.

A study of a K~+ channel in the basolateral membrane of renal proximal tubule recorded from single rat nephron in vitro / 第三军医大学学报

Objective To study the physiological properties of a potassium channel in the basolateral membrane (BLM) of proximal tubule. Methods Nephrons were dissected from rat kidney under a stereoscopic microscope. The standard configuration for single channel tight seal patch clamp technique was used to record channel currents from the BLM. Results A kind of potassium channel with low conductance and inward rectification was easily recorded in the BLM of the proximal tubule. The channel current occurred spontaneously in 81% seals made on the BLM. In the patches, with no spontaneous channel activity, the channel current occurred when the pressure increased. In the inside out configuration, run down was present in channel activity. The open dwelling time constants of the potassium channel were 0.524 ms and 5.087 ms, while the closed dwelling time constants were 1.029 ms and 16.500 ms. Conclusion A type of potassium channels with low conductance, stretch sensibility and chemistry sensibility, presenting kinetic properties as two opening and two closing states, are widely distributed in the basolateral membrane of proximal tubule.

Comments on the diagnosis for primary osteoporosis / 中华内分泌代谢杂志

In the diagnosis of primary osteoporosis,the secondary osteoporosis should be excluded first because it covers many kinds of diseases.At this point,the differential diagnosis is required and a wide variety of knowledge of internal medicine is prior to all others.Bone mineral density measurement is only one of the references for the diagnosis of primary osteoporosis instead of being the unique criterion.