Long-term follow-up after partial removal of a solitary kidney

Associations of MRI-derived kidney volume, kidney function, body composition and physical performance in ≈38 000 UK Biobank participants: a population-based observational study

Background

Kidney volume is used as a predictive and therapeutic marker for several clinical conditions. However, there is a lack of large-scale studies examining the relationship between kidney volume and various clinicodemographic factors, including kidney function, body composition and physical performance.

Methods

In this observational study, MRI-derived kidney volume measurements from 38 526 UK Biobank participants were analysed. Major kidney volume-related measures included body surface area (BSA)-adjusted total kidney volume (TKV) and the difference in bilateral kidneys. Multivariable-adjusted linear regression and cubic spline analyses were used to explore the association between kidney volume-related measures and clinicodemographic factors. Cox or logistic regression was used to identify the risks of death, non-kidney cancer, myocardial infarction, ischaemic stroke and chronic kidney disease (CKD).

Results

The median of BSA-adjusted TKV and the difference in kidney volume were 141.9 ml/m2 [interquartile range (IQR) 128.1-156.9] and 1.08-fold (IQR 1.04-1.15), respectively. Higher BSA-adjusted TKV was significantly associated with higher estimated glomerular filtration rate {eGFR; β = 0.43 [95% confidence interval (CI) 0.42-0.44]; P < .001}, greater muscle volume [β = 0.50 (95% CI 0.48-0.51); P < .001] and greater mean handgrip strength [β = 0.15 (95% CI 0.13-0.16); P < .001] but lower visceral adipose tissue volume [VAT; β = -0.09 (95% CI -0.11 to -0.07); P < .001] in adjusted models. A greater difference in bilateral kidney volumes was associated with lower eGFR, muscle volume and physical performance but with higher proteinuria and VAT. Higher BSA-adjusted TKV was significantly associated with a reduced risk of CKD [odds ratio (OR) 0.7 (95% CI 0.63-0.77); P < .001], while a greater difference in kidney volume was significantly associated with an increased risk of CKD [OR 1.13 (95% CI 1.07-1.20); P < .001].

Conclusion

Higher BSA-adjusted TKV and lower differences in bilateral kidney volumes are associated with higher kidney function, muscle volume and physical performance and a reduced risk of CKD.

Effect of extensive artery isolation during robotic-assisted partial nephrectomy on blood pressure of patients with poorly controlled hypertension: a preliminary study

PURPOSE

To investigate whether extensive renal artery isolation during robotic-assisted partial nephrectomy (RAPN) for renal cell carcinoma (RCC) affects blood pressure (BP) of patients with poorly controlled hypertension.

METHODS

We included 60 patients diagnosed with poorly controlled hypertension who underwent RAPN by an experienced surgeon. The renal artery of the treated kidney was sufficiently isolated. Systolic BP (SBP), diastolic BP (DBP) and antihypertensive medication information were obtained at baseline and 3- and 6-month follow-up after surgery. Primary endpoints were changes in BP, and medications. Predictors of SBP reduction at 3 months were assessed by multivariable logistic regression.

RESULTS

All 60 RAPN procedures were successful, with no major intra- or postoperative complications. Mean SBP and DBP decreased significantly at 3 months after surgery (SBP, -7.8 ± 6.3 mmHg, P < 0.001; DBP, -4.2 ± 6.4 mmHg, P = 0.01). SBP and DBP did not differ between 3- and 6-month follow-up. The mean number of BP medications prescribed was lower at 3 months than baseline (1.7 ± 1.0 vs 2.1 ± 1.0, P = 0.016). The only significant predictor of SBP reduction at 3 months was baseline SBP.

CONCLUSIONS

Renal denervation with extensive renal artery isolation during RAPN may improve BP control among patients with poorly controlled hypertension in short term.

The Role of Intraoperative Ultrasonography Associated with Clampless Technique in Three-Dimensional Retroperitoneoscopic Laparoscopic Enucleation of Completely Endophytic Renal Tumors

Objectives: To evaluate perioperative and functional outcomes of clampless laparoscopic tumor enucleation for completely endophytic renal tumors with the guide of intraoperative ultrasonography. Methods: We analyzed patients with clinically completely endophytic tumors, renal tumors, who underwent clampless three-dimensional (3D) retroperitoneoscopic laparoscopic tumor enucleation between January 2012 and January 2021. Patients with exophytic tumors were excluded. Intraoperative ultrasonography was used to map out the mass in all surgeries. Results: Overall, 57 patients underwent clampless 3D retroperitoneoscopic laparoscopic tumor enucleation. Mean surgical time was 131 minutes, and mean estimated blood loss was 202 mL. Mean hospital stay was 4.7 days. Major and minor postoperative complications occurred, respectively, in 3 and 10 cases. Only a patient had a positive surgical margin. One-year renal function did not differ from baseline. Conclusion: Our study showed that clampless laparoscopic enucleation guided by laparoscopic ultrasonography ensured satisfactory outcomes for completely intrarenal tumors, with excellent renal function preservation 1 year after surgery.

The Effect of Higher and Lower Protein Intakes on Nitrogen Balance in Renal Transplant Recipients with Underlying Graft Dysfunction

It is essential to determine the optimum protein intake in renal transplant recipients on steroids with renal dysfunction to maintain a neutral nitrogen balance. Our aim was to study the effect of higher (1.2 g/kg/day) and lower (0.8 g/kg/day) protein intakes on nitrogen balance, body composition, glomerular filtration rate (GFR), and proteinuria in renal transplant recipients with low estimated GFR (eGFR) (15-44 mL/min/1.73 m²). This prospective, open-labeled, randomized, cross-over, interventional study enrolled patients who were ≥4 months posttransplant with eGFR between 15 and 44 mL/min/1.73 m². Subjects were randomized to either Group 1 [Diet: proteins (1.2 g/kg/day), 35 kcal/kg/day] or Group 2 [Diet: proteins (0.8 g/kg/day) and 35 kcal/kg/day] for one month. Subjects crossed over to the other diet for 2^nd month. Body composition analysis, serum creatinine, blood urea nitrogen, serum protein, serum albumin, 24-h proteinuria, GFR measurement (24 h creatinine clearance), three-day diet recall and nitrogen balance estimation were performed at baseline and at the end of the first and 2^nd month. Statistical analysis was performed using IBM SPSS Statistics version 21. Thirty-two of 35 patients completed the study. Three-day diet recall showed that daily protein and energy consumption was 1.2 g/kg and 36.47 kcal/kg with higher and 0.94 g/kg and 31.94 kcal/kg with lower protein diets, respectively. Nitrogen balance was +3.61 g/day (P = 0.0002) with higher and +1.66 g/day with lower protein diets. A significant increase was noted in muscle mass (P = 0.0317), blood urea nitrogen (P = 0.0118), GFR (P = 0.0114), and proteinuria (P = 0.010) with a higher protein diet. Renal transplant recipients remained in positive nitrogen balance with both diets. Muscle mass and proteinuria increased significantly with a higher protein diet.

Histologic characterization and risk factors for persistent albuminuria in adolescents in a region of highly prevalent end-stage renal failure of unknown origin

Background

End-stage renal failure of unknown origin (ESRD-UO) is a public health problem in Mexico and many regions of the world. The prevalence of ESRD-UO in Aguascalientes Mexico is one of the highest worldwide, particularly in adults between 20 and 40 years of age.

Aim

To screen adolescents for chronic kidney disease (CKD), identify risk factors, and histologically characterize adolescents with persistent albuminuria (pACR).

Methodology

This is a cross-sectional, observational, and comparative study of adolescents in whom serum creatinine and the albumin creatinine ratio (ACR) were determined when screening for CKD. A clinical evaluation and risk factor survey were conducted. Patients with an abnormal ACR (≥ 30 mg/gr) or a low glomerular filtration rate (GFR) (≤75 ml/min/1.73 m2) were reevaluated and a renal ultrasound was obtained (rUS). A kidney biopsy was performed in patients with pACR.

Results

Five-hundred and thirteen (513) students were included, 19 had pACR and 494 were controls. The prevalence of pACR was 3.7% (95%CI 2.1 – 5.3). Only one patient had a decreased GRF. None of the patients with pACR had anatomical abnormalities of the urinary tract by rUS. Patients with pACR had a decreased total renal volume in comparison with the control group (150 vs 195 ml/m2, p &lt;0.01). Eighteen (18) kidney biopsies were performed, 72% had glomerulomegaly, and only one patient had mild fibrosis. Podocyte abnormalities were evident on electron microscopy: partial fusion (100%), microvillous degeneration (80%), and increased organelles (60%). Risk factors for pACR were: homestead proximity to maize crops, the use of pesticides at the father´s workplace, a family history of CKD, and blood pressure abnormalities. The body mass index and breastfeeding were protective factors.

Conclusions

The prevalence of pACR in adolescents in Aguascalientes is high, and histologic compromise is characterized by podocyte injury in the absence of fibrosis. The renal volume of pACR patients was decreased, suggesting oligonephronia. Exposure to environmental toxins such as pesticides, even prenatally, may be responsible for this pathological entity. Screening programs in adolescents by determining ACR are necessary in our milieu.

Renal Cell Cancer and Chronic Kidney Disease

The association between chronic kidney disease (CKD) and renal cell carcinoma (RCC) is bidirectional and multifactorial. Risk factors such as hypertension, diabetes mellitus, obesity, and smoking increase the risk of both CKD and RCC. CKD can lead to RCC via an underlying cystic disease or oxidative stress. RCC can cause CKD because of the tumor itself, surgical reduction of renal mass (either partial or radical nephrectomy), and perioperative acute kidney injury. Medical therapies such as immune checkpoint inhibitors and vascular endothelial growth factor inhibitors can lead to acute kidney injury and resultant CKD. Clinicians need to be aware of the complex, bidirectional interplay between both diseases.

Chronic Kidney Allograft Disease: New Concepts and Opportunities

Chronic kidney disease (CKD) is increasing in most countries and kidney transplantation is the best option for those patients requiring renal replacement therapy. Therefore, there is a significant number of patients living with a functioning kidney allograft. However, progressive kidney allograft functional deterioration remains unchanged despite of major advances in the field. After the first post-transplant year, it has been estimated that this chronic allograft damage may cause a 5% graft loss per year. Most studies focused on mechanisms of kidney graft damage, especially on ischemia-reperfusion injury, alloimmunity, nephrotoxicity, infection and disease recurrence. Thus, therapeutic interventions focus on those modifiable factors associated with chronic kidney allograft disease (CKaD). There are strategies to reduce ischemia-reperfusion injury, to improve the immunologic risk stratification and monitoring, to reduce calcineurin-inhibitor exposure and to identify recurrence of primary renal disease early. On the other hand, control of risk factors for chronic disease progression are particularly relevant as kidney transplantation is inherently associated with renal mass reduction. However, despite progress in pathophysiology and interventions, clinical advances in terms of long-term kidney allograft survival have been subtle. New approaches are needed and probably a holistic view can help. Chronic kidney allograft deterioration is probably the consequence of damage from various etiologies but can be attenuated by kidney repair mechanisms. Thus, besides immunological and other mechanisms of damage, the intrinsic repair kidney graft capacity should be considered to generate new hypothesis and potential therapeutic targets. In this review, the critical risk factors that define CKaD will be discussed but also how the renal mechanisms of regeneration could contribute to a change chronic kidney allograft disease paradigm.

Podocytopathies

Podocytopathies are kidney diseases in which direct or indirect podocyte injury drives proteinuria or nephrotic syndrome. In children and young adults, genetic variants in >50 podocyte-expressed genes, syndromal non-podocyte-specific genes and phenocopies with other underlying genetic abnormalities cause podocytopathies associated with steroid-resistant nephrotic syndrome or severe proteinuria. A variety of genetic variants likely contribute to disease development. Among genes with non-Mendelian inheritance, variants in APOL1 have the largest effect size. In addition to genetic variants, environmental triggers such as immune-related, infection-related, toxic and haemodynamic factors and obesity are also important causes of podocyte injury and frequently combine to cause various degrees of proteinuria in children and adults. Typical manifestations on kidney biopsy are minimal change lesions and focal segmental glomerulosclerosis lesions. Standard treatment for primary podocytopathies manifesting with focal segmental glomerulosclerosis lesions includes glucocorticoids and other immunosuppressive drugs; individuals not responding with a resolution of proteinuria have a poor renal prognosis. Renin-angiotensin system antagonists help to control proteinuria and slow the progression of fibrosis. Symptomatic management may include the use of diuretics, statins, infection prophylaxis and anticoagulation. This Primer discusses a shift in paradigm from patient stratification based on kidney biopsy findings towards personalized management based on clinical, morphological and genetic data as well as pathophysiological understanding.

The effect of partial nephrectomy on blood pressure in patients with solitary kidney

PURPOSE

To determine the effect of partial nephrectomy (PN) in the solitary kidney on systolic and diastolic blood pressures (SBP and DBP, respectively), and use of antihypertensive medications.

METHODS

We performed a retrospective cohort study of solitary kidney patients who underwent PN for kidney cancer from 1999-2015. Primary outcomes evaluated were blood pressure (BP) and antihypertensive medication changes from baseline up to 5 years postoperatively. Using a multivariable mixed-effects model to account for repeated measurements, we evaluated the effect of PN on the outcome measurements while controlling for baseline patient, pathologic, and perioperative characteristics.

RESULTS

292 patients who underwent PN on solitary kidneys met inclusion criteria (median [range] age, 63 [24-84] years; 179 men [61%]). SBP decreased immediately postoperatively (- 1.7 mmHg [- 2.6, - 0.7], p < 0.001), and further decreased by 0.04 mmHg per year (p = 0.01) postoperatively, for a total change of - 1.9 [- 3.9, 0.2] mmHg at 5 years (p = 0.01). DBP decreased immediately postoperatively (- 2.2 mmHg [- 2.7, - 1.7], p < 0.001), and then rebounded by 0.37 mmHg per year (p = 0.003) postoperatively, for a total change of - 0.4 [- 1.5, 0.7] mmHg at 5 years (p = 0.003). Antihypertensive medication use increased at 5 years (0.35 more medications per patient, p < 0.001).

CONCLUSIONS

Our results suggest a minimal change in BP after PN, although patients increased antihypertensive medication use. This data suggests damage to renal parenchyma or hilar nerves during PN did not significantly impact BP regulation in our cohort.

Birth Weight and Susceptibility to Chronic Kidney Disease

The worldwide prevalence of noncommunicable diseases (NCDs) is projected to increase substantially over the next few decades. Chronic kidney disease (CKD) is a key determinant of poor health outcomes for major NCD. Genetic predisposition and environmental exposures are contributory factors, but increasingly, it is being recognized that fetal development is also an important modulator of the NCD risk. Low birth weight (LBW) and CKD affect more disadvantaged populations and ethnic minorities and, therefore, causes a disproportionate burden on the poor. Human nephron number is highly variable and may range from under half a million to almost over two million. Significant variability is already present at birth, highlighting the importance of early nephrogenesis. Nearly 60% of nephrons are developed in the third-trimester of pregnancy. Nephron numbers increase in proportion to birth weight and gestational age. This wide-variability probably contributes to individual susceptibility to develop CKD where individuals with nephron numbers on the lower side of the spectrum are those at higher risk of developing kidney dysfunction at higher rate and progress more toward end-stage CKD. This article aims at discussing LBW and the susceptibility to CKD. Furthermore, in postnatal environment, the weight gain or change at adult life increases the metabolic demand and determines the phenotypic expression of disease along with the spectrum of nephron number. Hence, a cycle of hyperfiltration mechanism of these nephrons leads to proteinuria, glomerulo- sclerosis, and progressive development of larger glomeruli, a greater risk of proteinuria and progressive CKD. Therefore, LBW offspring are at risk of developing CKD (defined as albuminuria, a reduced glomerular filtration rate, or renal failure) in later life. Furthermore, the impact of prenatal programming is expected to be compounded with age, and the association of LBW with the risk of CKD seen in younger adults may become greater with age. It would be prudent, to adopt policies of intensified life-long surveillance of LBW people, anticipating this risk.

Obesity-Related Glomerulopathy: A Latent Change in Obesity Requiring More Attention

BACKGROUND

Obesity has become a major public health problem, and the prevalence of kidney diseases has increased in parallel. Among kidney diseases caused by metabolic disorders, obesity-related glomerulopathy (ORG) is secondary to obesity.

SUMMARY

ORG is mainly caused by glomerular hyperfiltration, dysregulation of hormone and cytokine secretion in adipose tissues, and ectopic lipid accumulation in renal cells. ORG is pathologically characterized by glomerular hypertrophy, with or without focal and segmental glomerulosclerosis. Patients with ORG usually present with proteinuria concomitant with metabolic disorders such as dyslipidemia and hypertension. Weight loss, RAAS inhibitors, and improved insulin resistance can reduce the progression of ORG.

CONCLUSION

ORG is a growing renal pathological change in obese individuals, and a comprehensive understanding of the disease is pivotal to avoid its occurrence and improve quality of life for those with obesity. Key Messages:This review comprehensively describes the characteristics of ORG in pathological changes, clinical manifestations, pathogeneses and treatments.

Clinical outcomes of repeat partial nephrectomy compared to initial partial nephrectomy of a solitary kidney

BACKGROUND

When local recurrence of renal cell carcinoma (RCC) occurs after nephron-sparing surgery (NSS) on the ipsilateral side, some surgeons hesitate to perform reoperative surgery because of possible difficulties. We aimed to evaluate the clinical outcomes of repeat partial nephrectomy (RePN) compared with those of initial partial nephrectomy (iPN) for RCC of a solitary kidney.

METHODS

Until September 2017, 1671 patients with renal tumors underwent NSS. Of these, 79 patients who underwent NSS for sporadic RCC of a solitary kidney were included. Parameters were compared using the Mann-Whitney U, Pearson Chi-square, and Fisher exact tests.

RESULTS

Eleven patients underwent RePN and 68 underwent iPN. The RePN group had a relatively smaller tumor size (p = 0.0432), longer operative time (p = 0.0432), and higher estimated blood loss (p = 0.0002) than the iPN group. No significant differences in the other clinical factors were found between the groups. The rates of perioperative complications greater than Clavien-Dindo grade II were 18.2% and 17.6% in the RePN group and iPN group, respectively. The mean decreasing rate of estimated glomerular filtration rate was not different between the groups at 3 and 6 months postoperatively. No significant differences were found in hemodialysis-free survival (p = 0.7392) and intrarenal recurrence-free survival (p = 0.4924) between the groups.

CONCLUSIONS

The clinical outcomes of RePN were not significantly different compared with those of iPN for patients with sporadic RCC of a solitary kidney. RePN is technically feasible with acceptable complication and local recurrence rates with better postoperative kidney function.

Fetal Renal DNA Methylation and Developmental Programming of Stress-Induced Hypertension in Growth-Restricted Male Mice

Fetal growth restriction (FGR) is associated with developmental programming of adult onset hypertension, which may be related to differences in nephron development. Prior studies showed that maternal nutrient restriction is associated with reduced nephrogenesis in rodents, especially in male progeny. We hypothesized that maternal genetic risk for FGR may similarly affect fetal kidney development, leading to adult onset hypertension. We employed an angiotensinogen (AGT) gene titration transgenic (TG) construct with 3 copies of the mouse AGT gene that mimics a common human genotype (AGT A[-6]G) associated with FGR. We investigated whether FGR in 2-copy (wild type, [WT]) progeny from 3-copy TG dams leads to developmental programming differences in kidney development and adult blood pressure compared with age- and sex-matched controls. Progeny were tested in the late fetal period (e17.5), neonatal period (2 weeks of age), and as young adults (12 weeks). We measured weights, tested for renal oxidative stress, compared renal DNA methylation profiles, counted the number of glomeruli, and measured adult blood pressure ± stress. Progeny from TG dams were growth restricted with evidence of renal oxidative stress, males showed fetal renal DNA hypermethylation, they had fewer glomeruli, and they developed stress-induced hypertension as adults. Their female siblings did not share this pathology and instead resembled progeny from WT dams. Surprisingly, glomerular counts in the neonatal period were not different between sexes or maternal genotypes. In turn, we suspect that differences in fetal renal DNA methylation may affect the long-term viability of glomeruli, rather than reducing nephrogenesis.

Management of small renal masses: An interventional radiologist's perspective

Renal cell carcinoma is relatively common malignancy. Its imaging features are often non-specific and can present a diagnostic dilemma for clinicians. Historically, all patients with a renal mass underwent radical nephrectomy. Advances in technology have allowed for an increase in partial nephrectomies and percutaneous ablations. This essay briefly describes some of the imaging findings of renal cell carcinoma and several of its mimics followed by an in-depth review of procedural management with a particular focus on recent advancements.

Long-term risks of kidney living donation: review and position paper by the ERA-EDTA DESCARTES working group

Two recent matched cohort studies from the USA and Norway published in 2014 have raised some concerns related to the long-term safety of kidney living donation. Further studies on the long-term risks of living donation have since been published. In this position paper, Developing Education Science and Care for Renal Transplantation in European States (DESCARTES) board members critically review the literature in an effort to summarize the current knowledge concerning long-term risks of kidney living donation to help physicians for decision-making purposes and for providing information to the prospective live donors. Long-term risk of end-stage renal disease (ESRD) can be partially foreseen by trying to identify donors at risk of developing ‘de novo’ kidney diseases during life post-donation and by predicting lifetime ESRD risk. However, lifetime risk may be difficult to assess in young donors, especially in those having first-degree relatives with ESRD. The study from Norway also found an increased risk of death after living donor nephrectomy, which became visible only after >15 years of post-donation follow-up. However, these findings are likely to be largely the result of an overestimation due to the confounding effect related to a family history of renal disease. DESCARTES board members emphasize the importance of optimal risk–benefit assessment and proper information to the prospective donor, which should also include recommendations on health-promoting behaviour post-donation.

Single-Center Long-Term Follow-Up of Kidney Donors in Argentina (Hospital Italiano de Buenos Aires)

INTRODUCTION

Living kidney donor (LKD) transplantation is increasing due to organ shortage. Clinical studies have shown that the risk of developing end-stage renal disease (ESRD) in donors is similar to that in the general population. Our goal was to evaluate postdonation renal outcomes assessed by glomerular filtration rate (GFR), proteinuria, and blood pressure.

METHODS

A total of 210 LKD transplants were performed at Hospital Italiano de Buenos Aires between 2000 and 2014. Postdonation outcomes were analyzed in 109 donors. GFR was assessed by 24-hour creatinine clearance (as 24-hour ClCr) and estimated using the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. Additionally, we correlated the predonation renal functional reserve (RFR) with postdonation GFR. Donor results were compared to the expected GFR (adjusted to age and single kidney). Other renal outcome indicators measured were albuminuria and blood pressure, and they were compared (predonation and postdonation) using univariate analysis.

RESULTS

A total of 109 patients were followed up for 47 ± 34 months (range, 12-168): 70% were female, age at donation was 48.58 years (range, 25-70), and predonation serum creatinine was 0.85 ± 0.17 mg/dL. Postnephrectomy GFR (24-hour ClCr) was significantly lower compared to predonation GFR (105.38 ± 21.78 mL/min/1.73 m² vs 90.14 ± 17.78 mL/min/1.73 m²). However, postdonation GFR was not significantly different compared to the expected GFR. No differences were found for blood pressure or albuminuria. Age >50 and an RFR (<20%) was associated with a lower GFR.

CONCLUSIONS

In this population of LKD, renal outcome (24-hour CrCl, albuminuria, and blood pressure) was within the expected outcome for healthy individuals after uninephrectomy.

The impact of donor and recipient weight incompatibility on renal transplant outcomes

BACKGROUND

Donor/recipient size mismatching and correlation to allograft outcome remains poorly defined. This study assessed the impact of donor body weight (DBW) to recipient body weight (RBW) ratio on allograft function and survival.

METHODS

A total of 898 deceased donor renal transplant recipients were included in the study. Patients were divided into quartiles depending on the ratio of DBW/RBW: Q1 (≤ 0.88), Q2 (0.89-1.00), Q3 (1.01-1.22) and Q4 (> 1.22). Donor and recipient characteristics were obtained from the national kidney transplant service database. Serum creatinine and estimated glomerular filtration rate (eGFR) at 1 and 5 years after transplant were compared.

RESULTS

Q4 patients had a higher eGFR 1 year post-transplant (median 59.5 ml/min, IQR 46.8-76.2) compared to Q1-Q3 which had median eGFRs of 54.3, 54.8 and 55.3 ml/min, respectively (p < 0.001). At 5 years post-transplant, there were modest differences in the eGFR across the four quartiles, Q1-4 with median eGFRs of 56.9, 61.1, 61.2 and 58.6 ml/min, respectively (p = 0.02). However, there were no significant differences in 1- and 5-year allograft survival between groups.

CONCLUSIONS

In the setting of deceased donor renal transplantation, mismatching of donor to recipient weight had no impact on 5-year allograft survival, but a low DBW/RBW ratio is modestly associated with lower eGFR.

Comparative Effectiveness of Surgical Treatments for Small Renal Masses

In the management of small renal masses (SRMs), treatment options include partial nephrectomy (PN), radical nephrectomy (RN), ablation, renal biopsy, and active surveillance. Large series retrospective and meta-analyses demonstrate PN may confer greater preservation of renal function, overall survival, and equivalent cancer control when compared with RN. As newer therapies emerge, we should critically evaluate the risks and benefits associated with the surgical management of SRMs among patients with competing comorbidities, complex tumors, and high-risk disease. Among younger patients with SRMs amenable to resection, optimization of postoperative patient health should be prioritized.

Podocyte and Parietal Epithelial Cell Interactions in Health and Disease

The glomerulus has 3 resident cells namely mesangial cells that produce the mesangial matrix, endothelial cells that line the glomerular capillaries, and podocytes that cover the outer surface of the glomerular basement membrane. Parietal epithelial cells (PrECs), which line the Bowman's capsule are not part of the glomerular tuft but may have an important role in the normal function of the glomerulus. A significant progress has been made in recent years regarding our understanding of the role and function of these cells in normal kidney and in kidneys with various types of glomerulopathy. In crescentic glomerulonephritis necrotizing injury of the glomerular tuft results in activation and leakage of fibrinogen which provides the trigger for excessive proliferation of PrECs giving rise to glomerular crescents. In cases of collapsing glomerulopathy, podocyte injury causes collapse of the glomerular capillaries and activation and proliferation of PrECs, which accumulate within the urinary space in the form of pseudocrescents. Many of the noninflammatory glomerular lesions such as focal segmental glomerulosclerosis and global glomerulosclerosis also result from podocyte injury which causes variable loss of podocytes. In these cases podocyte injury leads to activation of PrECs that extend on to the glomerular tuft where they cause segmental and/or global sclerosis by producing excess matrix, resulting in obliteration of the capillary lumina. In diabetic nephropathy, in addition to increased matrix production in the mesangium and glomerular basement membranes, increased loss of podocytes is an important determinant of long-term prognosis. Contrary to prior belief there is no convincing evidence for an active podocyte proliferation in any of the above mentioned glomerulopathies.

Collaborative Review of Risk Benefit Trade-offs Between Partial and Radical Nephrectomy in the Management of Anatomically Complex Renal Masses

BACKGROUND

While partial nephrectomy (PN) is the recommended treatment for many small renal masses, anatomically complex tumors necessitate a clear understanding of the potential risks and benefits of PN and radical nephrectomy (RN).

OBJECTIVE

To critically review the comparative effectiveness evidence of PN versus RN; to describe key trade-offs involved in this treatment decision; and to highlight gaps in the current literature.

EVIDENCE ACQUISITION

A collaborative critical review of the medical literature was conducted.

EVIDENCE SYNTHESIS

Patients who undergo PN for an anatomically complex or large mass may be exposed to perioperative and potential oncologic risks that could be avoided if RN were performed, while patients who undergo RN may forgo long-term benefits of renal preservation. Decision-making regarding the optimal treatment with PN or RN among patients with anatomically complex or large renal mass is highly nuanced and must balance the risks and benefits of each approach. Currently, high-quality evidence on comparative effectiveness is sparse. Retrospective comparisons are plagued by selection biases, while the one existing prospective randomized trial, albeit imperfect, suggests that nephron-sparing surgery may not benefit all patients.

CONCLUSIONS

For anatomically complex tumors, PN preserves renal parenchyma but may expose patients to higher perioperative risks than RN. The risks and benefits of each surgical approach must be better objectified for identification of patients most suitable for complex PN. A prospective randomized trial is warranted and would help in directing patient counseling.

PATIENT SUMMARY

Treatment decisions for complex renal masses require shared decision-making regarding the risk trade-offs between partial and radical nephrectomy.

Does significant renal ablation truly and invariably lead to hyperfiltration and progressive chronic kidney disease?

It is generally believed that significant renal ablation leads to hyperfiltration and eventually progressively worsening chronic kidney disease. The data behind this belief have not been scrutinized intensively. More importantly, the above belief leads many physicians to manage patients differently than they otherwise would manage. Here, we examine the data behind whether hyperfiltration occurs when patients lose kidney mass (by excision or by disease) and whether the hyperfiltration is uniformly injurious.

Contemporary Use of Partial Nephrectomy: Are Older Patients With Impaired Kidney Function Being Left Behind?

OBJECTIVE

To assess whether patient factors, such as age and preoperative kidney function, were associated with receipt of partial nephrectomy in a national integrated healthcare system.

MATERIALS AND METHODS

We identified patients treated with a radical or partial nephrectomy from 2002 to 2014 in the Veterans Health Administration. We examined associations among patient age, sex, race or ethnicity, multimorbidity, baseline kidney function, tumor characteristics, and receipt of partial nephrectomy. We estimated the odds of receiving a partial nephrectomy and assessed interactions between covariates and the year of surgery to explore whether patient factors associated with partial nephrectomy changed over time.

RESULTS

In our cohort of 14,186 patients, 4508 (31.2%) received a partial nephrectomy. Use of partial nephrectomy increased from 17% in 2002 to 32% in 2008 and to 38% in 2014. Patient race or ethnicity, age, tumor stage, and year of surgery were independently associated with receipt of partial nephrectomy. Black veterans had significantly increased odds of receipt of partial nephrectomy, whereas older patients had significantly reduced odds. Partial nephrectomy utilization increased for all groups over time, but older patients and patients with worse baseline kidney function showed the least increase in odds of partial nephrectomy.

CONCLUSION

Although the utilization of partial nephrectomy increased for all groups, the greatest increase occurred in the youngest patients and those with the highest baseline kidney function. These trends warrant further investigation to ensure that patients at the highest risk of impaired kidney function are considered for partial nephrectomy whenever possible.

Obesity-related glomerulopathy: clinical and pathologic characteristics and pathogenesis

The prevalence of obesity-related glomerulopathy is increasing in parallel with the worldwide obesity epidemic. Glomerular hypertrophy and adaptive focal segmental glomerulosclerosis define the condition pathologically. The glomerulus enlarges in response to obesity-induced increases in glomerular filtration rate, renal plasma flow, filtration fraction and tubular sodium reabsorption. Normal insulin/phosphatidylinositol 3-kinase/Akt and mTOR signalling are critical for podocyte hypertrophy and adaptation. Adipokines and ectopic lipid accumulation in the kidney promote insulin resistance of podocytes and maladaptive responses to cope with the mechanical forces of renal hyperfiltration. Although most patients have stable or slowly progressive proteinuria, up to one-third develop progressive renal failure and end-stage renal disease. Renin-angiotensin-aldosterone blockade is effective in the short-term but weight loss by hypocaloric diet or bariatric surgery has induced more consistent and dramatic antiproteinuric effects and reversal of hyperfiltration. Altered fatty acid and cholesterol metabolism are increasingly recognized as key mediators of renal lipid accumulation, inflammation, oxidative stress and fibrosis. Newer therapies directed to lipid metabolism, including SREBP antagonists, PPARα agonists, FXR and TGR5 agonists, and LXR agonists, hold therapeutic promise.

Functional and oncologic outcomes after nephron-sparing surgery in a solitary kidney: 10 years of experience

Objectives:

To evaluate functional and oncologic outcomes of partial nephrectomy (PN) in patients with a solitary kidney.

Materials and Methods:

A retrospective analysis of patients with a solitary kidney undergoing nephron-sparing surgery between March 2003 and March 2013 was performed. GFR was recorded before the procedure and 3 months after surgery, thus establishing a change (cGFR). Several variables that may influence cGFR were analyzed. Complications are herein described, namely bleeding, fistula, acute renal failure and end-stage renal disease (ESRD). Local recurrence and margin status are also described. Survival rates were calculated using the Kaplan Meier method (2 patients with metastasis at the time of surgery were excluded from the analysis).

Results:

Forty-five patients were available for analysis. Median follow-up was 27.56 months (r 3-96). Mean cGFR was-7.12mL/min (SD 2.1). Variables significantly related with lower GFR after surgery were loss of renal mass (p=0.01)) and male gender (p=0.03). Four patients (8.8%) experienced hemorrhage. Nine patients (20%) developed a urinary fistula. Only one patient with bleeding required open surgery. Two patients (4.4%) needed transient dialysis. Three patients (6.6%) developed ESRD. Four patients (8.8%) had positive surgical margins (PSMs) and four patients (88%) had local recurrence (2 of these had PSMs). Five patients (11.1%) died during follow-up. Four patients (8.8%) died because of renal cancer. Estimated 2-year overall survival, disease-free survival and cancer specific survival rates were 88.4% (CI 95% 70.5-96); 87.7% (CI 95% 68.1-96) and 92.4% (CI 95% 75-98), respectively.

Conclusion:

Loss of renal mass and male gender were associated with lower postoperative GFR. Our outcomes were comparable with those in the World literature.

Capillary Rarefaction Associates with Albuminuria: The Maastricht Study

Albuminuria may be a biomarker of generalized (i.e., microvascular and macrovascular) endothelial dysfunction. According to this concept, endothelial dysfunction of the renal microcirculation causes albuminuria by increasing glomerular capillary wall permeability and intraglomerular pressure, the latter eventually leading to glomerular capillary dropout (rarefaction) and further increases in intraglomerular pressure. However, direct evidence for an association between capillary rarefaction and albuminuria is lacking. Therefore, we examined the cross-sectional association between the recruitment of capillaries after arterial occlusion (capillary density during postocclusive peak reactive hyperemia) and during venous occlusion (venous congestion), as assessed with skin capillaroscopy, and albuminuria in 741 participants of the Maastricht Study, including 211 participants with type 2 diabetes. Overall, 57 participants had albuminuria, which was defined as a urinary albumin excretion ≥30 mg/24 h. After adjustment for potential confounders, participants in the lowest tertile of skin capillary recruitment during postocclusive peak reactive hyperemia had an odds ratio for albuminuria of 2.27 (95% confidence interval, 1.07 to 4.80) compared with those in the highest tertile. Similarly, a comparison between the lowest and the highest tertiles of capillary recruitment during venous congestion yielded an odds ratio of 2.89 (95% confidence interval, 1.27 to 6.61) for participants in the lowest tertile. In conclusion, lower capillary density of the skin microcirculation independently associated with albuminuria, providing direct support for a role of capillary rarefaction in the pathogenesis of albuminuria.

Does the Renal Parenchyma Adjacent to the Tumor Contribute to Kidney Function? A Critical Analysis of Glomerular Viability in Partial Nephrectomy Specimens

OBJECTIVE

To evaluate the viability of glomeruli in the peritumor parenchyma of partial nephrectomy specimens removed for renal cell carcinoma (RCC) and relate it to kidney function, to better understand the contribution of peritumor parenchyma to renal function.

MATERIALS AND METHODS

A retrospective analysis of 53 partial nephrectomies containing RCC was performed. Glomeruli within 0.25-cm increments from the tumor were quantified and histologically assessed for viability. Tumor size, minimum and maximum margin size, and pre- and postoperative estimated glomerular filtration rate (eGFR) were obtained.

RESULTS

Glomerular viability positively correlated with distance from tumor with mean viable glomeruli in successive 0.25-cm increments of 0-0.25 cm, 58%; 0.25-0.5 cm, 80%; 0.5-0.75 cm, 90%; and 0.75-1.0 cm, 92%. Glomerular viability near the tumor did not correlate with preoperative eGFR, whereas decreased viability further from the tumor did correlate with worse preoperative eGFR. Tumor size showed a nonstatistically significant positive trend with minimum (median 0.15 cm) and maximum margin (median 0.7 cm) sizes. Percent change of glomerular filtration rate did not correlate with margin size (P = .190).

CONCLUSION

Renal parenchyma immediately adjacent to RCC contains fewer viable glomeruli compared with the parenchyma further from the tumor. Based on this information, attempts to preserve all non-neoplastic renal parenchyma via a surgical margin approaching zero may not necessarily result in clinically relevant differences in the amount of viable glomeruli remaining or the renal function preserved.

Is microalbuminuria a risk factor for hypertension in children with solitary kidney?

BACKGROUND

The correlations between ambulatory blood pressure measurements (ABPM) and serum cystatin C (Cys C), serum creatinine (Cr), microalbumin (MA), and β2-microglobulin (β2-MG) levels in 24 h (24-h) urine were analyzed in children with solitary kidney (SK) and compared to healthy children.

METHODS

Fifty children with normal functioning SK and 25 controls were studied. The ABPM, serum Cys C, serum Cr, MA, and β2-MG levels in 24-h urine were measured in all children. Clinical symptoms and signs, laboratory results, urinary ultrasonography, voiding cystourethrography, and Dimercaptosuccinic acid (DMSA) scintigraphy results were recorded in the SK group. Four patients with Wilms' tumor and two with renal scarring were excluded from the study.

RESULTS

The mean ages of the SK group and controls were 9.6 ± 3.6 and 9.3 ± 3.3 years, respectively. The serum Cys C and Cr levels, 24-h urinary β2-MG and MA levels were similar in both groups (p > 0.05). However, 24-h urinary MA excretion was higher in patients living with SK more than 5 years (p = 0.01). Standard deviation scores of ABPM parameters showed no significant correlation with serum Cr, serum Cys C, MA, and β2-MG in 24-h urine of both groups.

CONCLUSIONS

Children with SK have increased 24-h urinary MA excretion in the long term, and need prolonged follow-up to detect early deterioration of renal function and to prevent end-organ damage later in life.

Patterns of recurrence and surveillance strategies for renal cell carcinoma following surgical resection

Renal cell carcinoma (RCC) remains one of the most lethal urologic malignancies, with up to 40% of patients eventually dying of cancer progression. Despite advances in the diagnosis, staging and treatment of patients with RCC, approximately a third of patients who undergo surgery for clinically localized RCC will suffer a recurrence. Timely identification of recurrences following surgical extirpation is imperative in the treatment of these patients. RCC is known to metastasize through hematogenous routes of spread to distant organ sites and via lymphatic channels to regional lymph nodes. The path of tumor escape is associated with diverse clinical outcomes and a unique tumor biology. A consensus on surveillance regimens for patients following surgical resection of localized disease is lacking. The most extensively used system for providing prognostic information regarding survival and recurrence of disease has historically been the tumor-node-metastasis (TNM) classification system. As a result, most contemporary surveillance protocols have tailored follow-up regimens according to stage-based stratifications. Numerous studies have recently demonstrated that certain clinical and histopathological factors can improve the prediction of tumor recurrence. The incorporation of these prognostic factors into stage-based stratification models should be better than stage alone in attempting to provide a rational approach to identifying treatable recurrences while minimizing unnecessary exams and tests, as well as patient anxiety. Advances in the understanding of the pathogenesis, behavior and molecular biology of RCC have paved the way for developments that may enhance early diagnosis and prognostication, and improve survival for patients. Lastly, molecular markers should, in the future, revolutionize surveillance protocols for RCC by tailoring follow-up to specific molecular classifications.

Compensatory renal growth after unilateral or subtotal nephrectomy in the ovine fetus

BACKGROUND

Clinical and experimental studies show that unilateral (1/2Nx) and subtotal nephrectomy (5/6Nx) in adults result in compensatory renal growth without formation of new nephrons. During nephrogenesis, the response to renal mass reduction has not been fully investigated.

METHODS

Ovine fetuses underwent 1/2Nx, 5/6Nx, or sham surgery (sham) at 70 d of gestation (term: 150 d), when nephrogenesis is active. At 134 d, renal function was determined, fetuses were killed, and kidneys were further analyzed at the cellular and molecular levels. Additional fetuses subjected to 5/6Nx were killed at 80 and 90 d of gestation to investigate the kinetics of the renal compensatory process.

RESULTS

At 134 d, in 1/2Nx, a significant increase in kidney weight and estimated glomerular number was observed. In 5/6Nx, the early and marked catch-up in kidney weight and estimated glomerular number was associated with a striking butterfly-like remodeling of the kidney that developed within the first 10 d following nephrectomy. In all groups, in utero glomerular filtration rates were similar.

CONCLUSION

Compensatory renal growth was observed after parenchymal reduction in both models; however, the resulting compensatory growth was strikingly different. After 5/6Nx, the remnant kidney displayed a butterfly-like remodeling, and glomerular number was restored.

Differential diagnosis of glomerular disease: a systematic and inclusive approach

BACKGROUND

Glomerular disease is a complex and evolving topic. In evaluating a specific case it is not unusual for the clinician to ask: 'Am I missing something? Should I biopsy? When? Should I treat first, then biopsy?' This work, which is both evidence and experience based, is intended to address each of these concerns and many other issues relevant to the differential diagnosis of glomerular disease.

SUMMARY

The central approach is the use of diagnostic algorithms that are based on quantitative measures routinely obtained early in the course of the diagnostic evaluation. The algorithms are designed to be easy to navigate, systematic, and inclusive. Also provided is a detailed and prioritized list of recommended diagnostic testing, and the rationale for each test.

KEY MESSAGE

This work is intended to facilitate accurate diagnosis in the individual patient presenting with evidence of glomerular disease.

A patient with nephrotic-range proteinuria and focal global glomerulosclerosis

A young male is evaluated for nephrotic-range proteinuria, hypercalciuria, and an elevated serum creatinine. A renal biopsy is performed and shows focal global glomerulosclerosis. The absence of nephrotic syndrome suggest that glomerulosclerosis was a secondary process. Further analysis of the proteinuria showed it to be due mainly to low-molecular weight proteins. The case illustrates the crucial role of electron microscopy as well as evaluation of the identity of the proteinuria that accompanies a biopsy finding of focal and global or focal and segmental glomerulosclerosis.

Nonneoplastic renal cortical scarring at tumor nephrectomy predicts decline in kidney function

CONTEXT

Evaluating nontumor portions of tumor nephrectomies is useful to diagnose nonneoplastic renal disease.

OBJECTIVE

To determine the medical renal disease frequency and to assess the prognostic significance of the various renal pathologic variables with long-term follow-up in tumor nephrectomy patients.

DESIGN

We reviewed nonneoplastic kidney sections of 456 consecutive cases from 1998 to 2008. Seventy-five cases were excluded (19 tumor compression, 25 no nonneoplastic tissue, 22 embolized kidneys, 9 end stage). Special staining, immunofluorescence, and/or electron microscopy was performed where appropriate. Vascular sclerosis was scored from mild to severe; interstitial fibrosis/tubular atrophy and global glomerulosclerosis (GS) were expressed as percentages. Follow-up, minimum 12 months, was evaluated in 156 cases. All renal pathologic variables were compared with regard to change in creatinine level from preoperative assessment to follow-up.

RESULTS

Of 381 cases, 57 had additional medical renal disease (15%), most frequently diabetic nephropathy (28) and hypertensive nephropathy (11). Postoperative creatinine levels increased significantly in patients with severe arteriosclerosis or arteriolosclerosis, >5% GS, and >10% interstitial fibrosis/tubular atrophy. Seventy-four percent of cases with additional nonneoplastic diagnoses showed severe arteriolosclerosis. Higher corresponding GS was seen in the more affected vascular cases: mean, 5.56% GS for mild versus 23% GS for severe. Three patients progressed to renal failure 1 to 4 years after nephrectomy, 2 with hypertensive nephrosclerosis and 1 with diabetic nephropathy.

CONCLUSIONS

Medical renal disease was identified in 15% of tumor nephrectomy specimens. The degrees of vascular sclerosis, GS, and interstitial fibrosis/tubular atrophy are predictive of elevated creatinine levels in postnephrectomy patients. Prognostic implications of the nontumor pathology are important in nephrectomized patients.

The biological consequence of obesity on the kidney

Obesity is a worldwide epidemic that is associated with several health issues, including kidney diseases. A specific kidney disease, referred to as obesity-related glomerulopathy, has been described in earlier publications. Obesity can affect the prognosis of other types of kidney diseases. Body-weight reduction with caloric restriction is an essential therapy, although strictly controlling food intake coupled with an appropriate evaluation is challenging. Low birthweight can be an important factor for obesity and results in kidney dysfunction. In this review, we analyse the consequences of obesity on kidney prognosis and potential strategies for combating obesity-associated kidney injury.

Dietary protein restriction and preservation of kidney function in chronic kidney disease

Dietary protein augmentation elicits an increase in single nephron glomerular filtration rate (GFR) and increased transglomerular pressure. This is similar to the hemodynamic response to reduction in renal mass. Among patients and experimental animals with proteinuric renal disease, these changes also cause an increase in glomerular permselectivity, which in experimental animals accelerates loss of renal function. A meta-analysis of a group of prospective randomized trials including over 2,000 patients found a significant effect on reducing dietary protein decreasing the risk of end-stage renal disease or death (defined as renal death). This differs somewhat in the outcomes of clinical trials using intermediate outcomes, such as the Modification of Diet in Renal Disease study that used change in GFR in part because of the initial hemodynamic effect of reduction in GFR mediated by dietary protein restriction.

Renal cell carcinoma : clinical features and management

In 1999 it was estimated that renal cell carcinoma (RCC) would account for 29,990 new cancer cases diagnosed in the United States (61% in men and 39% in women), and lead to 11,600 deaths. RCC accounts for 2-3% of all malignancies in adults and causes 2.3% of all cancer deaths in the United States annually (1). Approx 4% of all RCC cases are bilateral at some point in the life of the patient. Data from over 10,000 cases of renal cancer entered in the Connecticut Tumor Registry suggests an increase in the incidence of renal cancer from 1935-1989; in women the incidence increased from 0.7 to 4.2 in 100,000, and in men from 1.6 to 9.6 in 100,000 (2). Factors implicated in the development of RCC include cigarette smoking, exposure to petroleum products, obesity, diuretic use, cadmium exposure, and ionizing radiation (3-9).

Effects of partial nephrectomy on postoperative blood pressure

Purpose

The effects of partial nephrectomy (PN) on postoperative blood pressure (BP) are not known, and PN has the potential to worsen BP. We therefore sought to determine whether PN alters postoperative BP.

Materials and Methods

Patients who underwent PN for suspected malignancy at our institution from 2002 to 2008 were included. Data on BP and medication from before and after PN were retrieved from family physicians. BP and number of antihypertensive medications were compared after surgery with preoperative values by use of paired t tests and Chi-squared analyses, respectively.

Results

Of 74 patients undergoing PN and providing consent, 48 met the inclusion and exclusion criteria, with a median follow-up of 24 months. For the early postoperative period (1 month to 1 year after surgery), the mean BPs (132.3/77.0 mmHg) were unchanged compared with preoperative values (132.4/78.0 mmHg; p=0.59 systolic BP and p=0.30 diastolic BP). For the later postoperative period (beyond 1 year after surgery), the mean postoperative systolic BP was unchanged from the mean preoperative systolic BP (131.2 mmHg vs. 132.4 mmHg, respectively; p>0.30). However, the corresponding average diastolic BP was lower in the long term (78.0 mmHg versus 76.4 mmHg respectively; p=0.01). No significant difference in the mean number of BP medications prescribed preoperatively, at one year, and beyond one year was identified (p>0.37).

Conclusions

PN does not result in initial or long-term postoperative deterioration in BP.

Long-term outcomes of kidney donors

As the demand for kidney transplantation, particularly from living donors, continues to rise, there is increasing and much needed interest in accurately quantifying the long-term risks of kidney donation. We review the outcomes of kidney donors in the domains of survival, perioperative mortality, risk of end-stage renal disease, quality of life, course of diabetes mellitus in donors, pregnancy after donation, obesity, and prevalence of other health conditions.

Impact of nephron number dosing on cardiorenal damage and effects of ACE inhibition

BACKGROUND

Low nephron number is a recently identified cause of arterial hypertension. We set out to test the effect of nephron number dosing on blood pressure and cardiorenal damage including left ventricular (LV) remodeling and function. Because exact determination of nephron number in vivo is currently not possible, we combined the Munich Wistar Frömter (MWF) genetic rat model of inborn nephron deficit with the 5/6 renal ablation model (Nx).

METHODS

To obtain distinct levels of nephron number dose (NND), rats underwent either sham-operation (Wistar-Sham NND 1.0, and MWF-Sham NND 0.6, n = 15, respectively) or 5/6 renal ablation (Nx, Wistar-Nx NND 0.17, and MWF-Nx NND 0.1, n = 20, respectively). Two additional groups were treated orally for 4 weeks with 1 mg/kg/day ramipril (Wistar-Nx-ACEI and MWF-Nx-ACEI, n = 15, respectively).

RESULTS

Systolic blood pressure (SBP), LV hypertrophy, mRNA expression of atrial natriuretic factor, LV contractility, and relaxation were exponentially correlated with NND (P < 0.0001, respectively). Creatinine clearance (Cl(Cr)) decreased, albuminuria, renal interstitial fibrosis, tubulointerstitial damage, and glomerulosclerosis index increased with lowering NND in both Wistar-Nx (NND 0.17) and MWF-Nx (NND 0.1) animals. LV perivascular and interstitial fibrosis and sarcoplasmic reticular (SR) Ca(2+) cycling were not directly related to NND. Angiotensin-converting enzyme (ACE) inhibition with ramipril demonstrated strong cardio- and renoprotective effects even in the setting of very low NND of 0.1 in MWF-Nx animals.

CONCLUSIONS

These data demonstrate that reduced nephron number is a significant, independent determinant of blood pressure, cardiorenal damage, and LV dysfunction in a direct dose-dependent way.