Functional Renal Parenchyma Research Articles

Comparing renal function preservation after laparoscopic radio frequency ablation assisted tumor enucleation and laparoscopic partial nephrectomy for clinical T1a renal tumor: using a 3D parenchyma measurement system.

To compare the renal function preservation between laparoscopic radio frequency ablation assisted tumor enucleation and laparoscopic partial nephrectomy. Data were analyzed from 246 patients who underwent laparoscopic radio frequency ablation assisted tumor enucleation and laparoscopic partial nephrectomy for solitary cT1a renal cell carcinoma from January 2013 to July 2015. To reduce the intergroup difference, we used a 1:1 propensity matching analysis. The functional renal parenchyma volume preservation were measured preoperative and 12months after surgery. The total renal function recovery and spilt GFR was compared. Multivariable logistic analysis was used for predictive factors for renal function decline. After 1:1 propensity matching, each group including 100 patients. Patients in the laparoscopic radio frequency ablation assisted tumor enucleation had a smaller decrease in estimate glomerular filtration rate at 1day (-7.88 vs -20.01%, p < 0.001), 3months (-2.31 vs -10.39%, p < 0.001), 6months (-2.16 vs -7.99%, p = 0.015), 12months (-3.26 vs -8.03%, p = 0.012) and latest test (-3.24 vs -8.02%, p = 0.040), also had better functional renal parenchyma volume preservation (89.19 vs 84.27%, p < 0.001), lower decrease of the spilt glomerular filtration rate (-9.41 vs -17.13%, p < 0.001) at 12months. The functional renal parenchyma volume preservation, warm ischemia time and baseline renal function were the important independent factors in determining long-term functional recovery. The laparoscopic radio frequency ablation assisted tumor enucleation technology has unique advantage and potential in preserving renal parenchyma without ischemia damage compared to conventional laparoscopic partial nephrectomy, and had a better outcome, thus we recommend this technique in selected T1a patients.

Tc-99m Ethylenedicysteine and Tc-99m Dimercaptosuccinic Acid Scintigraphy-Comparison of the Two for Detection of Scarring and Differential Cortical Function.

Context:The differential cortical function obtained by Tc-99m EC is comparable to that of Tc-99m DMSA. However, identification of scars on Tc-99m EC images needs to be studied.Aims:The aim of the study is to evaluate role of Tc-99m EC for detection of scarring and differential cortical function by comparing with Tc-99m DMSA.Settings and Design:Prospective observational study of recurrent UTI; minimum 6 weeks after acute episode; when urine examination is negative for pus cells.Materials and Methods:Forty-seven children with normal positioned kidneys underwent Tc-99m EC and DMSA scintigraphy. The DRF and cortical phase images of both studies in the same image matrix size were evaluated by two independent observers for scarring; Tc-99m DMSA was considered as the gold standard.Statistical analysis used:MS Excel 2007 and GraphPad Instat V3.1 and ROC analysis.Results:There was no significant difference in the detection of scarring using two studies with Cohen's kappa coefficient (κ) 0.932. The sensitivity and specificity of Tc-99m EC for detection of scarring was 98.75% and 99.15%, respectively. There was good agreement between the differential cortical function calculated using two studies.Conclusions:The summed Tc-99m EC images with an acceptable high image contrast allow detection of cortical scarring in patients with normal kidney positions. It is an excellent single-modality comprehensive investigational agent for renal parenchymal defects, function, and excretion evaluation with the added advantages of lower cost, convenience, and low radiation exposure to the child.

Preventive hemostatic suture during open kidney resection as an option to preserve the renal function

Introduction . Renal cancer is one of the leading urological cancers due to annually increasing morbidity and mortality rates. Objective: to prove the efficiency of preventive hemostatic sutures during partial nephrectomy for maximal preservation of functional renal parenchyma in patients with renal cell carcinoma. Materials and methods. We developed and implemented a new technique of partial nephrectomy with preventive hemostatic suture, that allows not to clamp the renal pedicle, even in case of central tumor location. Main benefit of this technique is minimization of kidney function loss after the operation, which is the major aim of nephron sparing surgery. Study included 150 patients with pT1a–pT2bN0M0 kidney cancers. Central tumor location was in 64 patients, 45 patients had upper segment tumors and 41 lower segment tumors. 74 patients had T1a tumor stage, T1b and T2a stage observed in 53 and 4 patients respectively. Nineteen patients were diagnosed with cystic carcinoma. To evaluate renal function, dynamic nephroscintigraphy was carried out and volume indices were calculated by computed tomography data. Results. All patients underwent nephron sparing surgery using preventive hemostatic sutures. Mean operative time was 180 ± 40 minutes, mean anesthesia time was 190.5 ± 15.0 minutes. Mean blood loss was 250 ± 70 ml. We didn’t used arteria clamping and warm ischemia and there was no conversions to nephrectomy during all partial nephrectomies. Perfusion index of the kidney before the surgery was 54.13 ± 2.00 %, after the surgery 46.23 ± 3.00 %, renal index was 53.24 ± 4.00 % and 46.82 ± 2.39 %, respectfully. In our opinion decreasing of renal indexes in early postoperative period is associated with loss of kidney parenchyma due to the surgery. Mean kidney volume was 140 ± 30 cm3 with 120 ± 20 см3 functional parenchyma volume and mean tumor volume 40 ± 20 сm3. Functional parenchyma volume after surgery insignificantly decreased to 115 ± 20 сm3. Conclusion. Preventive hemostatic sutures during partial nephrectomy allows to remove the tumor in almost any part of the kidney. Rejection of renal hilum clamping minimizes ischemical damages of renal parenchyma.

Partial nephrectomy vs. radical nephrectomy for renal tumors: A meta-analysis of renal function and cardiovascular outcomes

ObjectivesThe widespread use of partial nephrectomy (PN) has led to the preservation of functional renal parenchyma. However, the benefits of PN on renal function and cardiovascular outcomes remain controversial. Thus, a meta-analysis was performed to reconcile the conflicting results. Materials and methodsPubMed, Embase, and the Cochrane Library were searched from inception to August 2015, and databases with all relevant comparative studies were included. The Mantel-Haenszel method with random-effects models was used to determine the pooled hazard ratios (HRs) for each outcome. ResultsIn total, 26 studies were pooled for new-onset chronic kidney disease, and 6 studies were pooled for cardiovascular outcomes. According to the pooled estimates, PN correlated with a 73% risk reduction of new-onset chronic kidney disease in all included patients (HR = 0.27, P<0.0001) and a 65% risk reduction in patients with tumors>4cm (HR = 0.35, P<0.0001) compared with radical nephrectomy. There were no significant differences between groups regarding postsurgery cardiovascular events (HR = 0.86, P = 0.238) and cardiovascular death (HR = 0.79, P = 0.196). Despite inherent selection biases, the pooled estimates were robust in sensitivity and subgroup analyses. ConclusionsOur findings suggest that PN lowers the postoperative risk of new-onset chronic kidney disease. Nevertheless, the protection of renal function by PN did not reduce the risk of cardiovascular outcomes. However, this result remains controversial, and additional large-scale evaluations are warranted.

Urinary Biomarkers at Early ADPKD Disease Stage

BackgroundAutosomal dominant polycystic kidney disease (ADPKD) is characterized by a decline in renal function at late disease stage when the majority of functional renal parenchyma is replaced by cystic tissue. Thus, kidney function, assessed by estimated glomerular filtration rate (eGFR) does not well represent disease burden in early disease. Here, we investigated various urinary markers for tubular injury and their association with disease burden in ADPKD patients at early disease course.MethodsADPKD patients between 18 and 40 years with an eGFR greater or equal to 70 ml per min per 1.73m2 were eligible for this cross-sectional study. Urinary Neutrophil Gelatinase-Associated Lipocalin (NGAL), Kidney Injury Molecule-1 (KIM-1), and Uromodulin (UMOD) were investigated by Enzyme-Linked Immunosorbent Assay. Clara Cell Protein 16 (CC16) was investigated by Latex Immuno Assay. Cryoscopy was performed to assess urine osmolality and Urinary Albumin-to-Creatinine Ratio (UACR) was calculated. The association and the predictive properties of the markers on eGFR and height adjusted total kidney volume (htTKV) was evaluated using multiple regression analysis, incorporating different control variables for adjustment. Internal bootstrapping validated the obtained results.ResultsIn 139 ADPKD patients (age 31 ±7 years, mean eGFR of 93 ± 19 ml per min per 1.73 m2) the total kidney volume was negatively correlated with eGFR and UMOD and positive associated with age, UACR, KIM-1 and urine osmolality after adjustment for possible confounders. Urine osmolality and htTKV were also associated with eGFR, whereas no association of CC16, NGAL and UMOD with eGFR or htTKV was found.ConclusionUACR and urinary KIM-1 are independently associated with kidney size but not with renal function in our study population. Urine osmolality was associated with eGFR and kidney volume following adjustment for multiple confounders. Despite statistical significance, the clinical value of our results is not yet conceivable. Further studies are needed to evaluate the property of the aforementioned biomarkers to assess disease state at early ADPKD stage.

PD29-01 PREDICTING RENAL PARENCHYMAL LOSS FOLLOWING NEPHRON SPARING SURGERY

You have accessJournal of UrologyKidney Cancer: Surgical Therapy I1 Apr 2015PD29-01 PREDICTING RENAL PARENCHYMAL LOSS FOLLOWING NEPHRON SPARING SURGERY Solomon Woldu, Alexa Meyer, Aaron Weinberg, Justin Matulay, Gregory Thoreson, Phillip Pierorazio, Mitchell Benson, G. Joel DeCastro, and James McKiernan Solomon WolduSolomon Woldu More articles by this author , Alexa MeyerAlexa Meyer More articles by this author , Aaron WeinbergAaron Weinberg More articles by this author , Justin MatulayJustin Matulay More articles by this author , Gregory ThoresonGregory Thoreson More articles by this author , Phillip PierorazioPhillip Pierorazio More articles by this author , Mitchell BensonMitchell Benson More articles by this author , G. Joel DeCastroG. Joel DeCastro More articles by this author , and James McKiernanJames McKiernan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1788AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Numerous studies indicate the importance of renal preservation in the surgical management of renal masses due to the correlation of functional renal parenchymal volume (FRPV) and renal function. We analyze the relationship between patient, operative, and tumor characteristics to determine which factors correlate with FRPV after nephron sparing surgery (NSS) using a 3-dimensional (3-D) volume assessment. METHODS Retrospective review of our institutional database from 1992-2014 of patients who underwent NSS for a localized renal mass with available contrast-enhanced preoperative and postoperative imaging (CT or MRI). Tumors were classified according to the R.E.N.A.L. nephrometry system. Using 3-D reconstruction software, preoperative and postoperative FRPV was calculated for the ipsilateral and contralateral kidney. RESULTS 158 patients were included in the study; mean age 58.7 years and mean follow-up of 40.1 months. The mean preoperative tumor volume was 34.0cc and mean tumor dimension was 3.4cm. The mean change in FRPV after NSS was -15.3% for the ipsilateral kidney and -6.8% for the total kidney volume. The mean R.E.N.A.L. nephrometry score was 6.2, with 60.1%, 34.2%, and 5.7% of tumors classified as low, medium, and high complexity, respectively. Increasing complexity was associated with increased FRPV loss (Table 1). On univariate analysis, ischemia time, tumor size, R.E.N.A.L. nephrometry score, complexity grouping, and the individual nephrometry components of tumor size, percent exophytic, depth, and whether tumor touches the renal artery or vein were all associated with larger FRPV loss. On multivariate analysis, only ischemia time, tumor size, and percent exophytic were independently associated with more FRPV loss (Table 2). CONCLUSIONS Using precise 3-D volumetric analysis, we find that ischemia time, tumor size, and the endophytic/exophytic properties of a localized renal mass are the most important determinants of FRPV loss. Examination of these predictors of volume loss may aid in prediction of functional outcomes following NSS. Table 1. Functional Renal Parenchymal Volume (FRPV) Loss by R.E.N.A.L. Nephrometry Complexity Grouping Low Medium High p-value Total Number 95 54 9 --- Mean % Change in Ipsilateral FRPV -11.53±13.91 -18.86±14.90 -33.93±16.59 <0.001 > 10% Loss 54.7% 70.4% 100.0% 0.010 > 20% Loss 23.2% 38.9% 88.9% <0.001 > 30% Loss 8.4% 20.4% 44.4% 0.005 > 40% Loss 3.2% 11.1% 33.3% 0.002 > 50% Loss 1.1% 3.7% 22.2% 0.002 Table 2. Multivariate Regression Analysis: Variables Influencing % Change in Ipsilateral Functional Renal Parenchymal Volume (FRPV) B 95% CI p-value CCI -0.075 -1.114, 0.964 0.887 Preoperative GFR -0.070 -.182, 0.043 0.222 Ischemia Time (minutes) -0.279 -.501, -0.057 0.014 Ischemia Type Cold reference Warm -3.165 -10.227, 3.898 0.377 EBL (cc) 0.005 -0.005, 0.014 0.325 Approach Open reference Lap -2.068 -9.506, 5.369 0.583 Robotic -0.768 -7.941, 6.406 0.833 Tumor Size (cm) -2.365 -3.845, -0.885 0.002 E-Score -6.771 -10.822, -2.719 0.001 N-Score 0.540 -2.346, 3.426 0.712 A-Score Anterior (a) reference Neither (x) -1.922 -8.660, 4.816 0.574 Posterior (p) -5.590 -10.921, -0.259 0.040 L-Score -1.245 -4.131, 1.640 0.395 H-Component -6.728 -15.059, 1.604 0.113 *CI = confidence interval, CCI = Charlson Comorbidity Index, GFR = glomerular filtration rate, unit in mL/min/1.73m2, EBL = estimated blood loss © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e648-e649 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Solomon Woldu More articles by this author Alexa Meyer More articles by this author Aaron Weinberg More articles by this author Justin Matulay More articles by this author Gregory Thoreson More articles by this author Phillip Pierorazio More articles by this author Mitchell Benson More articles by this author G. Joel DeCastro More articles by this author James McKiernan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Nephron-sparing surgery in renal cell carcinoma: current perspectives on technical issues.

Surgical resection remains the standard treatment for renal cell carcinoma. Although historically the concept of wide excision of the affected kidney dictated surgical thinking for more than half a century, a better understanding of the biology of this tumor, standardized staging, and changing patterns of presentation permit today a refined management approach with nephron-sparing surgery, thus limiting potential long-term morbidity by maximizing the preservation of functional renal parenchyma. This paper aims to review the current status of nephron-sparing surgery for solid renal masses with an emphasis on indications, preoperative assessment, and operative technical issues, summarizing the most recent existing data on the subject.

High-Resolution Imaging Using the VisualSonics Vevo 2100 on Isolated, Perfused Porcine Kidneys on Mechanical Circulatory Support.

Despite many improvements in the field of renal transplantation, the key problem that persists is the lack of organs for all the patients who need kidneys. This problem continues despite the addition of extended criteria donors and donation after cardiac death. Compounding this issue is the high discard rate and there are no good means to truly predict renal function using current pretransplantation testing parameters. In an isolated renal perfusion model using porcine kidneys, we tested the proof of principle that a Vevo 2100 high-frequency high-resolution ultrasound system (Fujifilm VisualSonics, Inc., Toronto, Canada) could assess renal parenchymal perfusion and flow in the central renal vessels which could not assess by conventional ultrasound. Images and velocities were easily obtained during these studies. High-frequency ultrasound imaging may be a feasible and reproducible method for assessing renal parenchymal integrity and function pretransplantation. Further studies are required to determine the sensitivity and specificity of this approach in comparison with traditional renal biopsy pretransplantation with the goal of increasing the identification and use of donated kidneys for transplantation.

Functional renal parenchyma volume as an indicator for partial nephrectomy in RCC.

e15594 Background: Evolution of surgical technique in kidney cancer pushes the limits of partial nephrectomy (PN) over the range of 7cm nowadays. Additional tools needed to help surgeon to verify r...

Robotic Partial Nephrectomy: Complex Hilar Mass

Introduction: Partial nephrectomy is currently the gold standard for definitive treatment of small renal masses. Robotic partial nephrectomy has allowed for the resection of increasingly more complex tumors. In the past, partial nephrectomy for completely endophytic tumors was routinely done through an open approach. However, advancement in laparoscopic ultrasound and robotics has allowed for resection of endophytic tumors more effectively. At our center, we have been performing robotic partial nephrectomy for tumors of increasing complexity, with higher nephrometry scores. We present our technique in the accompanying video. Materials and Methods: A 36-year-old male was found to have a 3.3 × 3.1 solid mass with solid enhancement in the midpole of the right kidney. The mass was completely endophytic, with a R.E.N.A.L. score of 10ah. His preoperative creatinine was 0.76 mg/dL and estimated glomerular filtration rate (eGFR) was >60 mL/minutes/1.73 m2. A decision was made to proceed with a robotic partial nephrectomy. Our positioning and port placement have been previously described for a partial nephrectomy. We docked the robot over the patient's right shoulder, using a three-armed approach. We used the laparoscopic ultrasound extensively to localize the tumor. A cap of normal parenchyma was first removed, and then the tumor was dissected off the hilum. We then performed our standard renorrhaphy technique. Results: Warm-ischemia time (WIT) was 35 minutes, and 70% of normal parenchyma was preserved. Estimated blood loss was 200 cc. There were no intraoperative complications. Final pathology revealed a 3.8 × 2.7-cm tumor, clear cell renal cell carcinoma, Fuhrman grade 3. The resection margins were negative. The patient's creatinine on discharge was 0.92 mg/dL, and eGFR was >60 mL/minutes/1.73 m2. A nuclear renogram is pending. Conclusions: Robotic partial nephrectomy for a completely endophytic hilar tumor is technically feasible. We incurred a longer WIT; however, we were able to preserve 70% of functional renal parenchyma with good short-term renal function. For this young patient, we feel this was a better alternative than performing a radical nephrectomy for his endophytic hilar tumor. Jihad H. Kaouk: Intuitive Surgical, Inc. (Consultant); Ethicon, Inc. (Speaker); Endocare, Inc. (Speaker). No competing financial interests exist for the other authors. Runtime of video: 9 mins 43 secs

Nonoperative treatment of blunt renal trauma with urinary extravasation in a child

The goal of renal trauma management is preservation of functional renalparenchyma with minimal morbidity. In children with grade IV renal injury, therole and timing of surgical or endourologic intervention is less established andremains controversial. We report a case of a urinary extravasation after bluntrenal trauma treated by internal ureteral stenting.

Change in renal parenchymal volume in living kidney transplant donors

Uninephrectomy would induce compensatory hypertrophy in the remaining kidney. We investigated the relationship between changes in renal parenchymal volume (RPV) and renal function after nephrectomy in living kidney donors. From July 2011 and January 2012, 45 kidney donors were enrolled in this study. Magnetic resonance scanning was performed before surgery, 3 and 7 days postoperatively, and RPV was calculated through disc summarize methods. Participants were followed up for 1 year. The RPV of the remaining kidney was 118.06 ± 23.51 cm(3) and then increased by 21.23 % to 143.13 ± 25.52 cm(3) at 3 days and by 24.17 % to 146.60 ± 25.86 cm(3) at 7 days. Multivariate regression analysis showed that preoperative RPV is positively related to its initial function (p = 0.037); the RPV at 7 days is directly related to its initial, preoperative size (p < 0.001). With respect to change in postoperative RPV, there is bigger gain in size in smaller kidneys (p = 0.005). The kidneys that has ≥20 % increase RPV after 7 days are more likely to show further increase in GFR at 1 year (p = 0.024). Uninephrectomy induced immediately increment in RPV of the remaining kidney. Donors with RPV increase of ≥20 % at 1 week have a more favourable renal function adaptation at 1 year.

Matrix-Producing Cells in Chronic Kidney Disease: Origin, Regulation, and Activation

Chronic injury to the kidney causes kidney fibrosis with irreversible loss of functional renal parenchyma and leads to the clinical syndromes of chronic kidney disease (CKD) and end-stage renal disease (ESRD). Regardless of the type of initial injury, kidney disease progression follows the same pathophysiologic processes characterized by interstitial fibrosis, capillary rarefaction and tubular atrophy. Myofibroblasts play a pivotal role in fibrosis by driving excessive extracellular matrix (ECM) deposition. Targeting these cells in order to prevent the progression of CKD is a promising therapeutic strategy, however, the cellular source of these cells is still controversial. In recent years, a growing amount of evidence points to resident mesenchymal cells such as pericytes and perivascular fibroblasts, which form extensive networks around the renal vasculature, as major contributors to the pool of myofibroblasts in renal fibrogenesis. Identifying the cellular origin of myofibroblasts and the key regulatory pathways that drive myofibroblast proliferation and transdifferentiation as well as capillary rarefaction is the first step to developing novel anti-fibrotic therapeutics to slow or even reverse CKD progression and ultimately reduce the prevalence of ESRD. This review will summarize recent findings concerning the cellular source of myofibroblasts and highlight recent discoveries concerning the key regulatory signaling pathways that drive their expansion and progression in CKD.

Serum prolactin and macroprolactin levels in diabetic nephropathy

Three molecular forms of prolactin with molecular weights of 23 (monomeric), 50 - 60 and > 100 kDA (macroprolactin) have been defined. Prolactin levels have been shown to be reduced in especially poorly controlled diabetes mellitus and the prevalence of macroprolactinemia in diabetic patients has been higher than the non-diabetic population. A total 234 Type 2 diabetic patients with different nephropathy stage was included in the study. Serum prolactin levels were analyzed by the Electrochemiluminescense method. Following polyethylene glycol (PEG) precipitation, recovery less than or equal to 40% was taken as evidence that a significant level of macroprolactin was present in the serum. Hyperprolactinemia and macroprolactinemia were detected in 40 (17%) and 13 (5.5%) patients, respectively. Macroprolactinemia was detected 13 of 40 patients with hyperprolactinemia (32.5%). Increased prolactin and macroprolactin levels in patients with moderate and severe renal failure (Stage 3, 4, and 5) according to the U.S. NKF-DOQI classification (p < 0.001). Prolactin and macroprolactin levels were not increased in patients with normoalbuminuria, microalbuminuria and macroalbuminuria (p > 0.05). Serum creatinine levels correleted positively with both prolactin (r = 0.51, p < 0.001) and macroprolactin levels (r = 0.43, p < 0.001). On the other hand, glomerular filtration rate correlated negatively with both prolactin (r = -0.54, p < 0.001) and macroprolactin levels (r = -0.44, p < 0.001). Albuminuria significantly related with neither prolactin nor macroprolactin levels (p > 0.05). In the present study, we found that not only serum prolactin but also serum macroprolactin levels increased especially in moderate to severe renal failure which was due to decreased glomerular filtration and renal parenchymal function resulting in an increased amount of monomeric prolactin and macroprolactin in the circulation in patients with Type 2 diabetes mellitus.

Nephron-sparing partial nephrectomy for bilateral Wilms' tumor

PurposePartial nephrectomy is increasingly used in children with bilateral Wilms' tumor (BWT) or contralateral recurrence. Nephron-sparing surgery seeks to achieve complete tumor removal while preserving functional renal parenchyma. Previous series have documented high rates of complications, recurrence, and mortality. MethodsTwelve patients (4 boys and 8 girls aged 9-42 months) with BWT or contralateral recurrence were treated at our institution with unilateral or bilateral partial nephrectomy. Preoperative imaging, operative notes, and pathology reports were reviewed. Outcomes analyzed included complications, recurrence, readmission rate, postoperative glomerular filtration rate (GFR), and survival. ResultsAll patients underwent successful nephron-sparing resection using standard techniques, with only 2 patients requiring unilateral nephrectomy. Median length of stay was 3 days. There were no major complications or urine leaks. Two patients were lost to follow-up. The remaining 10 were followed up for a median of 36 months (range, 3-79 months). There have been no recurrences or unplanned readmissions. Mean GFR is 107.7 (±32.8) mL/min per 1.73 m2, with no patient having a GFR below the lower limit of normal for age. ConclusionNephron-sparing resection is a safe and effective approach for children with BWT or contralateral recurrence and should be part of the multimodality therapeutic approach to this disease.

Bone marrow derived cells and reactive oxygen species in hypertrophy of contralateral kidney of transient unilateral renal ischemia-induced mouse

Renal mass reduction, such as unilateral nephrectomy induces a compensatory hypertrophy of remaining renal mass in response to overload induced by reduction of functional renal parenchyma. In our recent study, we observed that the recovery of ischemic injured kidney following transient unilateral renal ischemia took longer time than that following transient bilateral renal ischemia, indicating that non-damaged kidney may affect the damaged kidney and vice versa. Here, we investigated whether transient and partial renal parenchymal injury by transient unilateral renal ischemia (UI) results in the hypertrophy of its contralateral kidney (CLK) and reactive oxygen species is associated with the hypertrophy. Thirty minutes of UI resulted in gradual increase in CLK weight over time. UI increased superoxide formation, but not lipid peroxidation in the CLK. After UI, a significant increase in the number of NADPH oxidase 2 (Nox2)-expressing cells and the level of Nox2 expression in the CLK was observed. In parallel with the increases in Nox2-expressing cells in CLKs, infiltration of bone marrow-derived cells (BMDC) increased in CLK. Treatments with Mn(III) Tetrakis(1-methyl-4-pyridyl) porphyrin (MnTMPyP, a superoxide dismutase (SOD) mimetic) and apocynin (a putative NADPH oxidase inhibitor) inhibited UI-induced hypertrophy of CLK along with reduction in Nox2-positive cell, BMDC, amount of Nox2 expression and superoxide formation. In conclusion, transient and partial renal mass reduction by UI resulted in the hypertrophy of CLK through increased ROS formation by infiltrated cells into the interstitium of CLK.

1431 USE OF MAGNETIC RESONANCE RENOGRAPHY TO EVALUATE CHANGES IN FUNCTIONAL RENAL VOLUME AND GLOMERULAR FILTRATION RATES IN KIDNEYS FOLLOWING PARTIAL NEPHRECTOMY FOR RENAL TUMORS

INTRODUCTION AND OBJECTIVES: Volume of functional renal parenchyma (FRP) is an important factor in glomerular filtration rate (GFR) following partial nephrectomy (PN), but is commonly overlooked. The loss of FRP may occur secondary to a variety of causes including surgical excision as well as ischemic/reperfusion injury and acute tubular necrosis following PN. Conventional imaging studies (CT and MRI) can estimate kidney volumes, but cannot measure FRP. Magnetic resonance renography (MRR) is a novel, clinically practical method of measuring single kidney GFR (SK-GFR) as well as the volume of FRP. In this study, we aim to investigate the impact of operative factors and tumor characteristics on FRP and SK-GFR loss as measured by MRR. METHODS: Between October 2009 and August 2011, 15 patients (mean age 54.5, range 33-73) receiving PN for kidney tumors underwent pre-op and early (48 hours) post-op MRR in an IRBapproved, prospective study. MRR was performed at 1.5 T using coronal 3D imaging with TWIST after administration of 4mL of gadolinium contrast. Semi-automated in-house software was used to generate FRP volume and signal curves of the aorta, cortex and medulla, with conversion to SK-GFR using a tracer kinetic model as previously described. Linear regression and unpaired t-tests were utilized for statistical analysis. Tumor characteristics were quantified using nephrometry score. RESULTS: Mean decrease in FRP volume was significantly correlated with mean decrease in SK-GFR (r 0.51, p 0.031). Nephrometry score did not have a significant correlation with FRP loss and decrease in SK-GFR (r 0.4, 0.35), however, nearness to the collecting system had the strongest association with SK-GFR decrease (p 0.002) in the immediate post-op period. Volume loss of FRP was a mean of 17 cc greater with warm ischemia compared to cold ischemia (p 0.031), and demonstrated moderate correlation with ischemia time (r 0.46, p 0.05). CONCLUSIONS: A significant correlation exists between loss of FRP and decrease in SK-GFR immediately after PN. Nearness to the collecting system appears to be associated with an increased loss of FRP and SK-GFR. Pre-operative MRR to assess baseline SK-GFR and tumor characteristics may be useful in preventing unnecessary FRP loss by appropriately modifying surgical technique as well as factors such as ischemia type and time.

Renal parenchymal volume increases after contralateral nephrectomy: Assessment using three‐dimensional ultrasonography

We investigated the relationship between changes in renal parenchymal volume (RPV) and renal function after a unilateral nephrectomy. In all 46 consecutive patients undergoing unilateral nephrectomy were included. Three-dimensional ultrasonography was performed before surgery (n=46) and at 4.3±1.9 h (n=46), 2 days (n=39), and 7 days (n=43) after surgery to determine RPV. The mean RPV of the remaining kidney was 104.7 mL before surgery, 116.1 mL (+13.2%) at 4.3 h, 122.7 mL (+18.2%) at 2 days, and 117.6 mL (+13.3%) at 7 days after surgery. Sequential volume measurements during surgery (n=5) revealed that the transection of the renal artery was followed by an increase in RPV on the contralateral side at 60-90 min. Multivariate regression analysis revealed that RPV was positively associated with the single-kidney glomerular filtration rate (GFR) and body surface area in both the preoperative and postoperative states. An increase in the single-kidney GFR was not seen at 2 years in patients with an RPV increase of <5% at 1 week (102.9±8.4%, P=0.322), but was still significant in the other patients (115.5±21.0%, P<0.001). These findings suggest that kidney volume may increase due to enlargement of the vascular bed caused by increased renal blood flow during the acute phase. Thereafter, histological hypertrophic responses may replace the hemodynamic changes in the chronic phase.

Gross hematuria caused by a congenital intrarenal arteriovenous malformation: a case report

IntroductionWe report the case of a woman who presented with gross hematuria and was treated with a percutaneous embolization.Case presentationA 48-year-old Caucasian woman presented with gross hematuria, left flank pain, and clot retention. The patient had no history of renal trauma, hypertension, urolithiasis, or recent medical intervention with percutaneous instrumentation. The patient did not report any bleeding disorder and was not taking any medication. Her systolic and diastolic blood pressure values were normal at presentation. The patient had anemia (8 mg/dL) and tachycardia (110 bpm). She underwent color and spectral Doppler sonography, multi-slice computed tomography, and angiography of the kidneys, which showed a renal arteriovenous malformation pole on top of the left kidney.ConclusionsThe feeding artery of the arteriovenous malformation was selectively embolized with a microcatheter introduced using a right transfemoral approach. By using this technique, we stopped the bleeding, preserved renal parenchymal function, and relieved the patient's symptoms. The hemodynamic effects associated with the abnormality were also corrected.

The origin of interstitial myofibroblasts in chronic kidney disease

Chronic kidney diseases (CKD), independent of their primary cause, lead to progressive, irreversible loss of functional renal parenchyma. Renal pathology in CKD is characterized by tubulointerstitial fibrosis with excessive matrix deposition produced by myofibroblasts. Because blocking the formation of these scar-forming cells represents a logical therapeutic target for patients with progressive fibrotic kidney disease, the origin of renal myofibroblasts is a subject of intense investigation. Although the traditional view holds that resident fibroblasts are the myofibroblast precursor, for the last 10 years, injured epithelial cells have been thought to directly contribute to the myofibroblast pool by the process of epithelial-to-mesenchymal transition (EMT). The recent application of genetic fate mapping techniques in mouse fibrosis models has provided new insights into the cell hierarchies in fibrotic kidney disease and results cast doubt on the concept that EMT is a source of myofibroblast recruitment in vivo, but rather point to the resident pericyte/perivascular fibroblast as the myofibroblast progenitor pool. This review will highlight recent findings arguing against EMT as a direct contributor to the kidney myofibroblast population and review the use of genetic fate mapping to elucidate the cellular mechanisms of kidney homeostasis and disease.