Long-term effects of reduced renal mass in humans

Age and Pre-operative HbA1c levels affect renal function compensation in living kidney donors

OBJECTIVES

About 90% of Japanese kidney transplantations are conducted from living donors, and their safety and the maintenance of their renal function are critical. This study aims to identify factors that affect the compensation of renal function in living kidney donors after donor nephrectomy.

METHOD

In a retrospective cohort study, we reviewed data from 120 patients who underwent nephrectomy as living kidney transplant donors in our department from 2012 to 2021. Univariable and multivariable linear regression analyses were performed for donor factors affecting renal function after donor nephrectomy.

RESULT

The multivariable linear regression model revealed that the donor's age (p = 0.025), preoperative estimated Glomerular Filtration Rate (eGFR) (p < 0.001), and hemoglobin A1c (HbA1c) (p = 0.043) were independent risk factors for eGFR at six months after nephrectomy. The eGFR deterioration was more strongly associated with age in females than in males, whereas higher HbA1c values were more strongly associated with eGFR deterioration in males. Higher donor age and higher HbA1c each enhance the deterioration of eGFR six months after living donor nephrectomy. The data suggest that old age in especially female donors and preoperative higher HbA1c in male donors have a harmful impact on their renal function compensation.

Living kidney donors with HIV: experience and outcomes from a case series by the HOPE in Action Consortium

Background

Living kidney donation is possible for people living with HIV (PLWH) in the United States within research studies under the HIV Organ Policy Equity (HOPE) Act. There are concerns that donor nephrectomy may have an increased risk of end-stage renal disease (ESRD) in PLWH due to HIV-associated kidney disease and antiretroviral therapy (ART) nephrotoxicity. Here we report the first 3 cases of living kidney donors with HIV under the HOPE Act in the United States.

Methods

Within the HOPE in Action Multicenter Consortium, we conducted a prospective study of living kidney donors with HIV. Pre-donation, we estimated the 9-year cumulative incidence of ESRD, performed genetic testing of apolipoprotein L1 (APOL1), excluding individuals with high-risk variants, and performed pre-donation kidney biopsies (HOPE Act requirement). The primary endpoint was ≥grade 3 nephrectomy-related adverse events (AEs) in year one. Post-donation, we monitored glomerular filtration rate (measured by iohexol/Tc-99m DTPA [mGFR] or estimated with serum creatinine [eGFR]), HIV RNA, CD4 count, and ART.

Findings

There were three donors with two-four years of follow-up: a 35 year-old female, a 52 year-old male, and a 47 year-old male. Pre-donation 9-year estimated cumulative incidence of ESRD was 3.01, 8.01, and 7.76 per 10,000 persons, respectively. In two donors with APOL1 testing, no high-risk variants were detected. Biopsies from all three donors showed no kidney disease. Post-donation, two donors developed nephrectomy-related ≥grade 3 AEs: a medically-managed ileus and a laparoscopically-repaired incisional hernia. GFR declined from 103 to 84 mL/min/1.73 m2 at four years (mGFR) in donor 1, from 77 to 52 mL/min/1.73 m2 at three years (eGFR) in donor 2, and from 65 to 39 mL/min/1.73 m2 at two years (eGFR) in donor 3. HIV RNA remained <20 copies/mL and CD4 count remained stable in all donors.

Interpretation

The first three living kidney donors with HIV under the HOPE Act in the United States have had promising outcomes at two-four years, providing proof-of-concept to support living donation from PLWH to recipients with HIV.

Funding

National Institute of Allergy and Infectious Diseases, National Institutes of Health.

The Minnesota attributable risk of kidney donation (MARKD) study: a retrospective cohort study of long-term (> 50 year) outcomes after kidney donation compared to well-matched healthy controls

BACKGROUND

There is uncertainty about the long-term risks of living kidney donation. Well-designed studies with controls well-matched on risk factors for kidney disease are needed to understand the attributable risks of kidney donation.

METHODS

The goal of the Minnesota Attributable Risk of Kidney Donation (MARKD) study is to compare the long-term (> 50 years) outcomes of living donors (LDs) to contemporary and geographically similar controls that are well-matched on health status. University of Minnesota (n = 4022; 1st transplant: 1963) and Mayo Clinic LDs (n = 3035; 1st transplant: 1963) will be matched to Rochester Epidemiology Project (REP) controls (approximately 4 controls to 1 donor) on the basis of age, sex, and race/ethnicity. The REP controls are a well-defined population, with detailed medical record data linked between all providers in Olmsted and surrounding counties, that come from the same geographic region and era (early 1960s to present) as the donors. Controls will be carefully selected to have health status acceptable for donation on the index date (date their matched donor donated). Further refinement of the control group will include confirmed kidney health (e.g., normal serum creatinine and/or no proteinuria) and matching (on index date) of body mass index, smoking history, family history of chronic kidney disease, and blood pressure. Outcomes will be ascertained from national registries (National Death Index and United States Renal Data System) and a new survey administered to both donors and controls; the data will be supplemented by prior surveys and medical record review of donors and REP controls. The outcomes to be compared are all-cause mortality, end-stage kidney disease, cardiovascular disease and mortality, estimated glomerular filtration rate (eGFR) trajectory and chronic kidney disease, pregnancy risks, and development of diseases that frequently lead to chronic kidney disease (e.g. hypertension, diabetes, and obesity). We will additionally evaluate whether the risk of donation differs based on baseline characteristics.

DISCUSSION

Our study will provide a comprehensive assessment of long-term living donor risk to inform candidate living donors, and to inform the follow-up and care of current living donors.

Long-term Medical Outcomes of Living Kidney Donors

Historically, to minimize risks, living kidney donors have been highly selected and healthy. Operative risks are well-defined, yet concern remains about long-term risks. In the general population, even a mild reduction in glomerular filtration rate (GFR) is associated with cardiovascular disease, chronic kidney disease, and end-stage kidney disease (ESKD). However, reduction in GFR in the general population is due to kidney or systemic disease. Retrospective studies comparing donors with matched general population controls have found no increased donor risk. Prospective studies comparing donors with controls (maximum follow-up, 9 years) have reported that donor GFR is stable or increases slightly, whereas GFR decreases in controls. However, these same studies identified metabolic and vascular donor abnormalities. There are a few retrospective studies comparing donors with controls. Each has limitations in selection of the control group, statistical analyses, and/or length of follow-up. One such study reported increased donor mortality; 2 reported a small increase in absolute risk of ESKD. Risk factors for donor ESKD are similar to those in the general population. Postdonation pregnancies are also associated with increased risk of hypertension and preeclampsia. There is a critical need for long-term follow-up studies comparing donors with controls from the same era, geographic area, and socioeconomic status who are healthy, with normal renal function on the date matching the date of donation, and are matched on demographic characteristics with the donors. These data are needed to optimize donor candidate counseling and informed consent.

Nephron mass determines the excretion rate of urinary extracellular vesicles

Urinary extracellular vesicles (uEVs) are emerging as non-invasive biomarkers for various kidney diseases, but it is unknown how differences in nephron mass impact uEV excretion. To address this, uEV excretion was measured before and after human kidney donor nephrectomy and rat nephrectomy. In male and female donors, uEVs were quantified in cell-free spot and 24-h urine samples using nanoparticle tracking analysis (NTA), EVQuant, and CD9-time-resolved fluorescence immunoassay. Female donors had significantly lower total kidney volume (TKV) and excreted 49% fewer uEVs than male donors. uEV excretion correlated positively with estimated glomerular filtration rate (eGFR), creatinine clearance, and TKV (R's between 0.6 and 0.7). uEV excretion rate could also be predicted from spot urines after multiplying spot uEV/creatinine by 24-h urine creatinine. Donor nephrectomy reduced eGFR by 36% ± 10%, but the excretion of uEVs by only 16% (CD9+ uEVs -37%, CD9- uEVs no decrease). Donor nephrectomy increased the podocyte marker WT-1 and the proximal tubule markers NHE3, NaPi-IIa, and cubilin in uEVs two- to four-fold when correcting for the nephrectomy. In rats, the changes in GFR and kidney weight correlated with the changes in uEV excretion rate (R = 0.46 and 0.60, P < 0.01). Furthermore, the estimated degree of hypertrophy matched the change in uEV excretion rate (1.4- to 1.5-fold after uninephrectomy and four-fold after 5/6th nephrectomy). Taken together, our data show that uEV excretion depends on nephron mass, and that nephrectomy reduces uEV excretion less than expected based on nephron loss due to compensatory hypertrophy. The major implication of our findings is that a measure for nephron mass or uEV excretion rate should be included when comparing uEV biomarkers between individuals.

Long-term compensation of renal function after donor nephrectomy

Background

Living donors are the major source of kidneys in countries with a shortage of deceased donors. Kidney donation after careful donor selection is generally accepted as a safe procedure, but the physiologic consequences after donor nephrectomy are not fully verified. In this study we retrospectively reviewed the renal function of the residual kidney in living donors.

Methods

Post-nephrectomy laboratory data of 1,175 living donors (60.7%) from 1,933 living donors who received uninephrectomy from January 1999 to December 2017 at Yonsei University, Severance Hospital, Korea were retrospectively collected. Post-nephrectomy renal function was monitored by the relative ratio of estimated glomerular filtration rate (e-GFR; pre-nephrectomy e-GFR ratio vs. post-nephrectomy e-GFR) that was calculated by the Modification of Diet in Renal Disease formula.

Results

During 36.3±37.6 months of mean follow-up, two cases (0.17%, 2/1,175) of renal failure developed. The mean e-GFR decreased to 64.3±14.2 mL/min/1.73 m² immediately after nephrectomy from 99.2±19.9 mL/min/1.73 m² of the pre-nephrectomy e-GFR. Early decrement of e-GFR was prominent in male and obese donors (body mass index >25 kg/m², P<0.05). The e-GFR ratio increased according to post-nephrectomy duration, and the mean increment degree of e-GFR ratio after nephrectomy calculated by linear regression analysis was 1.94% per year. Unlike the early decrement of e-GFR ratio after nephrectomy, donor factors such as degree of obesity and donor sex did not affect the late increment of e-GFR ratio after nephrectomy (P>0.05).

Conclusions

Our data showed that long-term compensation of the renal function after nephrectomy occurs independently of preoperative donor characteristics.

Physiology and Pathophysiology of Compensatory Adaptations of a Solitary Functioning Kidney

Children born with a solitary functioning kidney (SFK) have an increased risk of hypertension and kidney disease from early in adulthood. In response to a reduction in kidney mass, the remaining kidney undergoes compensatory kidney growth. This is associated with both an increase in size of the kidney tubules and the glomeruli and an increase in single nephron glomerular filtration rate (SNGFR). The compensatory hypertrophy and increase in filtration at the level of the individual nephron results in normalization of total glomerular filtration rate (GFR). However, over time these same compensatory mechanisms may contribute to kidney injury and hypertension. Indeed, approximately 50% of children born with a SFK develop hypertension by the age of 18 and 20–40% require dialysis by the age of 30. The mechanisms that result in kidney injury are only partly understood, and early biomarkers that distinguish those at an elevated risk of kidney injury are needed. This review will outline the compensatory adaptations to a SFK, and outline how these adaptations may contribute to kidney injury and hypertension later in life. These will be based largely on the mechanisms we have identified from our studies in an ovine model of SFK, that implicate the renal nitric oxide system, the renin angiotensin system and the renal nerves to kidney disease and hypertension associated with SFK. This discussion will also evaluate current, and speculate on next generation, prognostic factors that may predict those children at a higher risk of future kidney disease and hypertension.

Living Kidney Donor Evaluation

Long-term safety of living kidney donation (LKD), especially for young donors, has become a real matter of concern in the transplant community and may contribute to creating resistance to LKD. In this context, the criteria that govern living donor donations must live up to very demanding standards as well as adjust to this novel reality. In the first part, we review the existing guidelines published after 2010 and critically examine their recommendations to see how they do not necessarily lead to consistent and universal practices in the choice of specific thresholds for a parameter used to accept or reject a living donor candidate. In the second part, we present the emergence of a new paradigm for LKD developed in the 2017 Kidney Disease: Improving Global Outcomes guidelines with the introduction of an integrative risk-based approach. Finally, we focus on predonation renal function evaluation, a criteria that remain central in the selection process, and discuss several issues surrounding the donor candidate's glomerular filtration rate assessment.

Renal risk profiling in newly diagnosed hypertensives in an urban population in Nigeria

Introduction

Hypertension is a cause and consequence of chronic kidney disease globally. The other factors that work in concert with hypertension to cause CKD are yet to be clearly elucidated. Studies have identified proteinuria, dyslipidemia, obesity, smoking and family history of CKD as renal risk factors. Due to the high morbidity and mortality associated with occurrence of CKD including the enormous financial burden involved in its management, the knowledge of prevention and understanding of the risk factors for development of CKD is highly essential. Therefore, Identifying well defined risk factors that display strong graded association with the occurrence and progression of CKD can help in elucidating potential targets for disease modification.

Objective

The aim of this study was to determine the prevalence of renal risk factors and their impact on kidney function in newly diagnosed hypertensive Nigerians.

Methods

This was a case control study of two hundred and fifty newly diagnosed hypertensive Nigerians recruited from two contiguous hospitals in an urban setting in south western Nigeria. Another group of two hundred and fifty apparently healthy age and sex matched normotensive Nigerians in the same community were recruited as controls.

Results

Seventy (28%) of the newly diagnosed hypertensives had estimated glomerular filtration rate of less than 60ml/min, while 42.4% and 18.8% of the subjects and the controls had microalbuminuria respectively. The newly diagnosed hypertensives had significantly higher prevalence of analgesic use (86.4% versus 41.6%, p < 0.001), alcohol consumption (20.8% versus 12%, p = 0.008), use of canned salted food (18.8% versus 8.4%, p= 0.001) and central obesity (36.1% versus 26.8%, p= 0.025) compared to controls.

Conclusion

There is a significant occurrence of modifiable renal risk factors in newly diagnosed hypertensives and this offers a platform for instituting preventive strategies in the community.

Clinical consequences of developmental programming of low nephron number

Nephron number in humans varies up to 13-fold, likely reflecting the impact of multiple factors on kidney development, including inherited body size and ethnicity, as well as maternal health and nutrition, fetal exposure to gestational diabetes or preeclampsia and other environmental factors, which may potentially be modifiable. Such conditions predispose to low or high offspring birth weight, growth restriction or preterm birth, which have all been associated with increased risks of higher blood pressures and/or kidney dysfunction in later life. Low birth weight, preterm birth, and intrauterine growth restriction are associated with reduced nephron numbers. Humans with hypertension and chronic kidney disease tend to have fewer nephrons than their counterparts with normal blood pressures or kidney function. A developmentally programmed reduction in nephron number therefore enhances an individual's susceptibility to hypertension and kidney disease in later life. A low nephron number at birth may not lead to kidney dysfunction alone except when severe, but in the face of superimposed acute or chronic kidney injury, a kidney endowed with fewer nephrons may be less able to adapt, and overt kidney disease may develop. Given that millions of babies are born either too small, too big or too soon each year, the population impact of altered renal programming is likely to be significant. Many gestational exposures are modifiable, therefore urgent attention is required to implement public health measures to optimize maternal, fetal, and child health, to prevent or mitigate the consequences of developmental programming, to improve the health future generations.

[Long term renal function outcomes and predictive factors of chronic renal failure after living kidney donation]

INTRODUCTION

Living donor kidney transplants give the best results in term of renal function and are the principal solutions for the transplant shortage. However, donors selection and kidney function evaluation after surgery are essential. The objective of this study was to evaluate the prevalence and to identify the predictive factors of chronic renal failure for the donor, after living donor nephrectomy.

MATERIALS AND METHODS

It was a retrospective and monocentric study, including all the patients who underwent a living donor nephrectomy from 2007 to 2015 at the hospital of the Conception in Marseille. The primary study endpoint was renal function mesured by the glomerular filtration rate (GFR in mL/min) at 1 year and 5 years after surgery. The identification of moderate kidney failure predictive factors was achieved by an univariate and a multivariate analysis under Cox model.

RESULTS

Ninety-one patients were included. There was 40,7 % of men and media nage was 49 years (21; 70). Median pre-operative GFR was 94mL/min (67; 160). Median follow-up was 24 months (1; 120). Post operative GFR at 1 month, 1 year and 5 years was respectively 63mL/min (33; 90), 65mL/min (38; 107) and 67mL/min (56; 126) ans significantly lower than pre operative GFR (respectively P<0,001, P<0,001 et P=0,005). The prevalence of moderate kidney failure at 1 month, 1 year and 5 years was respectively 43,1 %, 33,3 % ans 25 %. In univariate and multivariate analysis, the only parametre significantly associated with a 1 year GFR>60mL/min wasp re operative GFR>90mL/min OR 3,61 IC95 % (1,27; 10,28) P=0,02.

CONCLUSION

Living donor nephrectomy leads to an important medium to long term loss of renal function. Donors with pre operative GFR<90mL/min should benefit from a rigorous supervision and nephrological care.

LEVEL OF EVIDENCE

3.

Kidney donor outcomes ≥ 50 years after donation

Many living kidney donors (LDs) are young at donation; yet there are little data on long-term LD follow-up. We report on 66 LDs who donated ≥50 years ago: 22 (33.3%) are still alive (current age, 78.5 ± 7.25 years); 39 (59%) died (mean age at death, 74.2 ± 12.3 years); and 5 are lost to follow-up (mean age at last contact, 68.7 ± 4.6 years). Those who died were older at donation (P < .001). Causes of death included 12 (30.8% of deaths) cardiovascular diseases, 9 (23.0%) respiratory failures, 5 (12.8%) malignancies and 4 (10.3%) infections, and 9 (23%) were unknown or miscellaneous. Forty-nine living donors (74%) developed hypertension at a mean age of 59.9 ± 14.0 years; 12 (18%) developed diabetes at a mean age of 62 ± 19.4 years; and 11 (16.7%) developed proteinuria at a mean age of 60.6 ± 18.2 years-each at a similar incidence as seen in the age-matched general population. At last follow-up, the eGFR by CKD-EPI (mean ± SD) for donors currently alive was 60.2 ± 13.4 mL/min/1.73 m² ; for those that died, 54.0 ± 21.5 mL/min/1.73 m² ; for those lost to follow-up, 55.6 ± 7.5 mL/min/1.73 m² . ESRD developed in 2 (3.3%). SF-36 quality of life health survey scores (n = 21) were similar to the age-matched general population.

Adherence to Medical Appointments Among Living Kidney Donors After Donation Under a Monitored Approach and Long-term Clinical Outcomes: A Brazilian Single-center Cohort Study

BACKGROUND

There is little information about living donor long-term follow-up among Brazilian living donors. The aim of this study was to evaluate the main outcomes among living donors and to measure their adherence to regular medical appointments.

METHODS

This is a Brazilian single-center cohort study that included 397 living donors with 87.1 months of follow-up and measured adherence to clinical appointments. Before 2010, the appointments were scheduled only spontaneously; after that an approach was structured to check the returns of donors, who were monitored actively. We also evaluated long-term outcomes such as survival and chronic kidney disease development and, secondarily, the incidences of hypertension, diabetes mellitus (DM), and dyslipidemia after donation.

RESULTS

The donors' adherence to annual clinical appointments was 75.8% (54.7% of them presenting annual regularity). Before 2010 the adherence was lower than 40%; 10-year cumulative incidences of hypertension, DM, and dyslipidemia were 20.4%, 5.7%, and 23.5%, respectively. The crude mortality was 1% and 10-year donor survival was 98.5%. The incidence of chronic kidney disease 5 years after donation was 19%, with 16.4% of patients staged in 3a and 2.6% in 3b.

CONCLUSION

A structured approach to check donor returns to long-term clinical appointments has doubled the adherence to visits returns (compared to historical data). We identified lower incidence of arterial hypertension and DM among donors as compared with the incidence of arterial hypertension and DM in the Brazilian general population, but the 5-year chronic kidney disease incidence was considered high, taking into consideration data that have been published in the last years.

Comparison of long-term kidney functions after radical nephrectomy and simple nephrectomy

Objective

To determine if there is a difference in proceeding to CKD between patients who had undergone radical nephrectomy (RN) and simple nephrectomy (SN) for different indications by comparing the short- and long-term renal function.

Materials and Methods

We retrospectively analyzed the records of all patients who underwent nephrectomy (either for malign or benign indications) in our clinic between January 2007 and September 2017. The patients were divided into 2 groups according the type of surgery: 1) Radical nephrectomy Group, 2) Simple Nephrectomy Group. Renal function was evaluated with Glomerular Filtration Rate (GFR) calculated using the MDRD formula.

Results

A total of 276 patients were included in the study. There were 202 patients in RN Group and 74 patients in SN Group. The mean age of the patients in RN Group and SN Group were age 59,2 ± 11,5 and 49,9 ± 15,1 years, respectively (p = 0.001). GFR levels of patients in RN Group versus SN Group were as follows: Preoperative period: 84.9 vs. 81 mL/min/1.73 m²; postoperative 1st day: 60.5 vs. 84.4 mL/min/1.73 m², postoperative 1st month 58.9 vs. 76 mL/min/1.73 m², postoperative 1st year: 59.5 vs. 74.1 mL/min/1.73 m²; at last control 60.3 and 76.1 mL/min/1.73 m². While preoperative GFR was found to be similar in two groups (p = 0.26), postoperative GFR values were found to be significantly lower in Group RN (p < 0.001). In comparison of the decrease in GFR in two groups at last follow-up, significantly higher decrease was observed in RN Group, 29% vs. 6%, (p < 0.05).

Conclusion

The decrease in GFR exists more common and intensive after RN compared to SN. In long-term, compensation mechanisms that develop after sudden nephron loss like radical nephrectomy deteriorates kidney function more than gradual nephron loss as in benign etiologies which indicates simple nephrectomy.

Hypertension after kidney donation: Incidence, predictors, and correlates

Incidence of postdonation hypertension, risk factors associated with its development, and impact of type of treatment received on renal outcomes were determined in 3700 kidney donors. Using Cox proportional hazard model, adjusted hazard ratios (HRs) for cardiovascular disease (CVD); estimated glomerular filtration rate (eGFR) <60, <45, <30 mL/min/1.73m2 ; end stage renal disease (ESRD); and death in hypertensive donors were determined. After a mean (standard deviation [SD]) of 16.6 (11.9) years of follow-up, 1126 (26.8%) donors developed hypertension and 894 with known antihypertensive medications. Hypertension developed in 4%, 10%, and 51% at 5, 10, and 40 years, respectively, and was associated with proteinuria, eGFR < 30, 45, and 60 mL/min/1.73m2 , CVD, and death. Blood pressure was <140/90 mm Hg at last follow-up in 75% of hypertensive donors. Use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (compared to other antihypertensive agents) was associated with a lower risk for eGFR <45 mL/min/1.73m², HR 0.64 (95% confidence interval [CI] 0.45-0.9), P = .01, and also less ESRD; HR 0.03 (95% CI 0.001-0.20), P = .004. In this predominantly Caucasian cohort, hypertension is common after donation, well controlled in most donors, and factors associated with its development are similar to those in the general population.

Progression to chronic kidney disease in patients undergoing nephrectomy for small renal masses: a price to pay for a therapeutic success?

Nephrectomy, which constitutes a gold-standard procedure for the treatment of renal-cell carcinoma (RCC), has been widely discussed in the past decade as a significant risk factor of the development of chronic kidney disease (CKD). RCC is the third most common genitourinary cancer in the United States, with an estimated more than 65,000 new cases and 14,970 deaths. The aim of this review was to precisely and comprehensively summarize the status of current knowledge in CKD risk factors after nephrectomy, the advantages of minimally invasive vs. radical nephrectomy, post-nephrectomy biomarkers of CKD, ways of post-operative CKD prevention and, therefore, better understand why various aspects of CKD after nephrectomy. The majority of current studies indicated a better long-term kidney function preservation in patients undergoing partial nephrectomy in comparison to those after radical nephrectomy. Furthermore, a nephron-sparing surgery should be a preferred first-line procedure among young patients with small renal masses. As partial nephrectomy is followed by a greater risk of adverse outcomes relative to radical nephrectomy, a potential survival benefit should always be considered especially in the elderly or patients with comorbidities.

Long-Term Consequences of Complex Living Renal Donation: Is It Safe?

INTRODUCTION

As there is a paucity of literature regarding the long-term outcomes of complex living donors, we conducted this study to assess the effect of kidney donation on the complex living kidney donor.

MATERIALS AND METHODS

This retrospective study was conducted in Narayan Health Hospital, Kolkata, Eastern India. The cohort consisted of complex living kidney donors who donated kidneys between the years 2007 and 2012. All donors were 60 years old or older, or were younger than 60 years and had comorbidities like hypertension and obesity. After a minimum follow-up of 5 years, all donors underwent evaluation. Data pertaining to hypertension, new-onset diabetes, body mass index (BMI), estimated glomerular filtration rate (eGFR) and albuminuria, and cardiac events were compared from the time of donation till 5 years post-transplant.

RESULTS AND DISCUSSION

We found a statistically significant increase in blood pressure, number of antihypertensives used, and mean BMI at follow-up. Diabetes mellitus was developed in 22.3% of donors. The mean GFR also decreased significantly at follow-up. There were 42 elderly donors (≥60 years) and 23 ≤ 59 years of age. There was a significant fall of eGFR in both groups, but the percentage fall was similar in both groups. A significant percentage of donors developed proteinuria, the majority being hypertensives.

CONCLUSION

Procurement of kidneys from marginal donors should be done cautiously, and donors should be assessed for morbidity and mortality in the future, as we found a statistically significant deterioration in renal function, blood pressure, and BMI over long-term follow-up.

Causes and timing of end-stage renal disease after living kidney donation

End-stage renal disease (ESRD) is a risk after kidney donation. We sought, in a large cohort of kidney donors, to determine the causes of donor ESRD, the interval from donation to ESRD, the role of the donor/recipient relationship, and the trajectory of the estimated GFR (eGFR) from donation to ESRD. From 1/1/1963 thru 12/31/2015, 4030 individuals underwent living donor nephrectomy at our center, as well as ascertainment of ESRD status. Of these, 39 developed ESRD (mean age ± standard deviation [SD] at ESRD, 62.4 ± 14.1 years; mean interval between donation and ESRD, 27.1 ± 9.8 years). Donors developing ESRD were more likely to be male, as well as smokers, and younger at donation, and to have donated to a first-degree relative. Of donors with a known cause of ESRD (n = 25), 48% was due to diabetes and/or hypertension; only 2 from a disease that would have affected 1 kidney (cancer). Of those 25 with an ascertainable ESRD cause, 4 shared a similar etiology of ESRD with their recipient. Almost universally, thechange of eGFR over time was stable, until new-onset disease (kidney or systemic). Knowledge of factors contributing to ESRD after living kidney donation can improve donor selection and counseling, as well as long-term postdonation care.

Ambulatory blood pressure monitoring in living kidney donors: What changes in 10 years?

In renal transplantation, living donations have more significant benefits compared to cadaveric donations. However, a probable increase in blood pressure following donation should also be kept in mind. In this study, we investigated the long-term changes in blood pressure in living kidney donors using ambulatory blood pressure monitoring and we explored the e-GFR and albuminuria/proteinuria measurements at 3 time points. Twenty-eight living kidney donors and 39 healthy individuals were evaluated and compared at the baseline and later at the 10th year. At the 10th year, creatinine levels were higher and eGFR levels were lower in the donors, whereas the systolic and diastolic measurements of the donors and controls and the prevalence of nondipping in the donors and controls were similar. Our study may be underpowered due to its small population size. However, our results at the 10th year follow-up indicated that the risk of hypertension might not seem to have increased in the well-selected donors. In addition, the majority of our donors had preserved their GFR values. Therefore, we can suggest that living kidney donation appears to be safe in well-selected patients over a 10-year time frame.

Life with one kidney

Life with a solitary functioning kidney (SFK) may be different from that when born with two kidneys. Based on the hyperfiltration hypothesis, a SFK may lead to glomerular damage with hypertension, albuminuria and progression towards end-stage renal disease. As the prognosis of kidney donors was considered to be very good, having a SFK has been considered to be a benign condition. In contrast, our research group has demonstrated that being born with or acquiring a SFK in childhood results in renal injury before adulthood in over 50% of those affected. Most congenital cases will be detected during antenatal ultrasound screening, but up to 38% of cases of unilateral renal agenesis are missed. In about 25-50% of cases of antenatally detected SFK there will be signs of hypertrophy, which could indicate additional nephron formation and is associated with a somewhat reduced risk of renal injury. Additional renal and extrarenal anomalies are frequently detected and may denote a genetic cause for the SFK, even though for the majority of cases no explanation can (yet) be found. The ongoing glomerular hyperfiltration results in renal injury, for which early markers are lacking. Individuals with SFK should avoid obesity and excessive salt intake to limit additional hyperfiltration. As conditions like hypertension, albuminuria and a mildly reduced glomerular filtration rate generally do not result in specific complaints but may pose a threat to long-term health, screening for renal injury in any individual with a SFK would appear to be imperative, starting from infancy. With early treatment, secondary consequences may be diminished, thereby providing the optimal life for anyone born with a SFK.

Effect of nephrectomy for retroperitoneal sarcoma on post-operative renal function

BACKGROUND AND OBJECTIVES

Surgical resection of retroperitoneal sarcomas (RPS) often involves removal of the ipsilateral kidney. We evaluated the long-term post-operative renal function in patients who underwent a nephrectomy as part of their en-bloc resection of RPS.

METHODS

Retrospective review of an institutional database identified RPS patients who underwent nephrectomy for curative intent from 1990 to 2014. The primary outcome measured was chronic kidney disease (CKD) calculated by the glomerular filtration rate (GFR).

RESULTS

Of the 47 patients in our study, 19 (40%), 18 (38%), and 10 (21%) patients had a preoperative CKD stage 1, 2, and 3, respectively. The GFR decreased by an average of 33.4 mL/min/1.73 m² with 66% of patients demonstrating mild progression of their renal impairment. Only three (6%) patients progressed to CKD stage 4 or 5, one of which required life-long dialysis.

CONCLUSION

Nephrectomy as part of an en-bloc resection is associated with a decrease in GFR that is not clinically significant. Fear of kidney failure should not prevent a surgeon from performing a nephrectomy in the treatment of RPS.

[Outcome of living kidney donors for transplantation]

Nowadays, several treatments exist to treat terminal chronic renal failure. Best results for the recipients are obtained with kidney transplantation concerning mortality and quality of life. Transplantation is also the cheaper option for society. Living kidney donation raises the issue of the becoming of the donor, an absolutely healthy subject who gets to a surgical procedure. The becoming of living kidney donors has been compared with the one of controls subjects in several studies. The evaluations focused on the complications of nephrectomy in the short and long-term: kidney failure, hypertension, proteinuria, possibility of pregnancy, quality of life, and mortality. The first results did not show any risk linked to kidney donation, compared to general population. However, since 2013, kidney donors were found at higher risk for kidney failure and even for mortality, compared with controls selected like donor candidates. The risk of kidney donation is nevertheless acceptable and minimal, on the condition of rigorous selection of candidates and regular follow-up.

Histologic Abnormalities in Non-neoplastic Renal Parenchyma and the Risk of Chronic Kidney Disease Following Radical Nephrectomy

OBJECTIVE

To assess the association of histopathological parameters in non-neoplastic renal parenchyma with the development of new-onset chronic kidney disease (CKD) after radical nephrectomy.

PATIENTS AND METHODS

Data were extracted from 222 patients who underwent radical nephrectomy. The Modification of Diet in Renal Disease formula was used. The study end point was development of CKD, defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m². A renal pathologist assessed three histologic features in the non-neoplastic parenchyma, namely global glomerulosclerosis (GS), arteriosclerosis (AS), and interstitial fibrosis (IF). For GS assessment, the percent of affected glomeruli was determined. AS was graded and divided into three groups, namely 1-0%-25%, 2-26%-50%, and 3-greater than 50%. IF was evaluated as absent or present.

RESULTS

After a mean follow-up of 49.06 months, the mean eGFR rate decrease was 26.5% after radical nephrectomy. Almost half of the patients (53.8%) developed CKD. For each 2.5% increase in GS, each point increase in Charlson comorbidity index (CCI), and each 10-year increase in patient's age, the eGFR decreased 28%, 33%, and 39%, respectively (P < .05). In a univariate analysis, age, CCI, GS, AS, IF, hypertension, and diabetes mellitus were associated with new-onset CKD after radical nephrectomy (P < .05). After multivariate logistic regression, CCI, GS, and baseline eGFR were associated with new-onset CKD after radical nephrectomy.

CONCLUSION

Histopathological evaluation of non-neoplastic renal parenchyma in patients who undergo radical nephrectomy can be used to predict the development of new-onset CKD.

Male Gender and Body Mass Index Are Associated With Hypertension and Reduced Kidney Function 5 or More Years After Living Kidney Donation

BACKGROUND

The objective of this study was to evaluate renal function and to explore the relationship between some risk factors in kidney donors 12.37 ± 7.60 years after donation.

PATIENTS AND METHODS

In a cross-sectional study conducted in a transplant unit, 77 nephrectomized subjects were assessed ≥5 years after donation to evaluate their renal function and the presence or absence of hypertension, dyslipidemia, and microalbuminuria.

RESULTS

Twenty donors had an estimated glomerular filtration rate of <60 mL/min/1.73 m(2). Nine donors showed urinary albumin excretion of >20 μg/min (11.68%). Subjects with an EGFR of <60 mL/min were predominantly male and hypertensive and showed higher body mass index (BMI), higher uric acid, higher total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C), and logarithm of triglycerides/HDL-C (log TG/HDL-C) ratios than donors with an EGFR of >60 mL/min. Hypertensive donors were older and had higher BMI, higher UA serum values, higher TC/HDL-C and log TG/HDL-C ratios and microalbuminuria than nonhypertensive donors (P < .005). A multivariate analysis was conducted and, after final adjustment, a filtration rate of <60 mL/min was 3.05 times higher in men than women, increased 10% for each 1-unit increase in BMI and was positively associated with log (TG/HDL-C). The frequency of hypertension increased by 10% for each 1-unit increase in BMI and was positively associated with microalbuminuria.

CONCLUSION

In this sample of kidney donors from a single transplant unit, ≥5 years after donation, male sex and high BMI were positively associated with the presence of kidney failure.

Predictors of low estimated glomerular filtration rate after living kidney donation in a Southeast Asian population from Singapore

AIM

Post-donation kidney function has not been well characterized in the Southeast Asian population. We studied a retrospective cohort of 174 living kidney donors at Singapore General Hospital between 1976 and 2012, evaluated patterns of change in kidney function using quantile regression analysis and investigated for predictors of low estimated glomerular filtration rate (eGFR) < 60 mL/min per 1.73m² . Median follow-up time (range) was 7.8 (0.1-33.8) years following donor nephrectomy.

RESULTS

Of the donors, 43.1% regained 75% or more of pre-nephrectomy eGFR after 5 years post-donation; 9.8% exhibited 100% recovery to pre-nephrectomy eGFR. High pre-nephrectomy eGFR was protective for risk of low post-donation eGFR, with a 6% risk reduction for each unit increase in pre-nephrectomy eGFR (odds ratio, 0.94; 95% confidence interval, 0.91-0.97; P = 0.002). This relationship was stronger in the short term (>6 months to < 5 years) than medium to long term (5 years or longer) (interaction P = 0.052).

CONCLUSION

In general, kidney function is well preserved following kidney donation in Southeast Asian donors. Pre-nephrectomy eGFR is a good predictor of post-donation eGFR, especially in the short-term.

Deterioration in the renal function and risk of microalbuminuria after radical, simple and donor nephrectomy: A long-term outcome

Objectives:

Evaluation of deterioration in renal function and risk of micro albuminuria after radical, simple and donor nephrectomy.

Materials and Methods:

A total of 594 patients underwent nephrectomy (159 radical, 318 simple and 117 donors) from February 2009 to December 2012 in our institute. First 300 eligible patients were divided in 3 groups, each having equalled number of patients. Group 1 was consisted of patients who underwent radical, group 2 had simple and group 3 had donor nephrectomy. These patients were followed up to February 2015. Follow up of all the patients were done at first month following the surgery and then in every six months subsequently. The follow up included the measurement of serum creatinine and urinary micro albumin in a spot urine sample. CKD-EPI equation was used for calculation of e GFR.

Results:

At the end of our study, 35 patients (41.6%) in group 1 and 8 patients (8.69%) in group 2 developed CKD stage 3. During the follow-up period, 41% patients in group 1, 13% in group 2 and 4% in group 3 developed MA.

Conclusion:

Nephron-sparing surgery should be the standard treatment of renal tumors, wherever possible. There should be a regular follow up of the patients after radical, simple and donor nephrectomy because of risk of CKD. Early consultation with nephrologists should be done by the patients who are suffering from MA after nephrectomy.

Cardiovascular Risk Assessment in Elderly Living Kidney Donors: Risk Comparison Before and After Donation Using QRISK Equation

OBJECTIVES

This study aimed to assess whether donor age would increase the risk of cardiovascular comorbidities during the first few years after donation. Cardiovascular risk was calculated using the QRISK tool (University of Nottingham and EMIS, Nottingham, UK).

MATERIALS AND METHODS

Data were collected from 221 living renal transplant donors at St. George's University Hospital NHS Foundation Trust between 2008 and 2012 before and after donation (at 6, 12, and 24 mo). QRISK scores were calculated for each patient at these time points before stratifying our patients into 2 cohorts: cohort A (age ≤ 59 y) and cohort B (age ≥ 60 y). QRISK scores were then compared using unpaired t tests.

RESULTS

Before donation, mean QRISK scores were 3.4% in cohort A and 12.4% in cohort B (P < .001). At 6, 12, and 24 months after kidney donation, the risks were 3.3% and 12.2% (P < .001), 3.8% and 13.6% (P < .001), and 5% and 15.4% (P < .001) in cohort A versus cohort B.

CONCLUSIONS

When we analyzed risk before donation, both age groups showed a significant increase in cardiovascular risk at 24 months. This subtle increase in cardiovascular risk in the 2 groups may be attributed to changing patient demographics, such as the increasing age of patients, rather than the donation itself. Elderly kidney donors, therefore, are a key source of donation after satisfactory cardiovascular work-up. However, elderly kidney donors will require long-term postoperative follow-up care and specific counseling aimed at reducing modifiable cardiovascular risk factors.

Investigating kidney donation as a risk factor for hypertension and microalbuminuria: findings from the Swiss prospective follow-up of living kidney donors

OBJECTIVES

To assess the role of nephrectomy as a risk factor for the development of hypertension and microalbuminuria.

DESIGN

Prospective, long-term follow-up study.

SETTING

Swiss Organ Living-Donor Health Registry.

PARTICIPANTS

All living kidney donors in Switzerland between 1993 and 2009.

INTERVENTIONS

Data on health status and renal function before 1 year and biennially after donation were collected.

PRIMARY AND SECONDARY OUTCOME MEASURES

Comparison of 1-year and 5-year occurrences of hypertension among normotensive donors with 1-year and 5-year estimates from the Framingham hypertension risk score. Multivariate random intercept models were used to investigate changes of albumin excretion after donation, correcting for repeated measurements and cofactors such as age, male gender and body mass index.

RESULTS

A total of 1214 donors contributed 3918 data entries with a completed biennial follow-up rate of 74% during a 10-year period. Mean (SD) follow-up of donors was 31.6 months (34.4). Median age at donation was 50.5 years (IQR 42.2-58.8); 806 donors (66.4%) were women. Donation increased the risk of hypertension after 1 year by 3.64 (95% CI 3.52 to 3.76; p<0.001). Those participants remaining normotensive 1 year after donation return to a risk similar to that of the healthy Framingham population. Microalbuminuria before donation was dependent on donor age but not on the presence of hypertension. After nephrectomy, hypertension became the main driver for changes in albumin excretion (OR 1.19; 95% CI 0.13 to 2.25; p=0.03) and donor age had no effect.

CONCLUSIONS

Nephrectomy propagates hypertension and increases susceptibility for the development of hypertension-induced microalbuminuria.

Renal Damage Frequency in Patients with Solitary Kidney and Factors That Affect Progression

Background. The aim of this study is to assess renal damage incidence in patients with solitary kidney and to detect factors associated with progression. Methods. Medical records of 75 patients with solitary kidney were investigated retrospectively and divided into two groups: unilateral nephrectomy (group 1) and unilateral renal agenesis/dysplasia (group 2). According to the presence of kidney damage, each group was divided into two subgroups: group 1a/b and group 2a/b. Results. Patients in group 1 were older than those in group 2 (p = 0.001). 34 patients who comprise group 1a had smaller kidney size (p = 0.002) and higher uric acid levels (p = 0.028) than those in group 1b at presentation. Uric acid levels at first and last visit were associated with renal damage progression (p = 0.004, 0.019). 18 patients who comprise group 2a were compared with those in group 2b in terms of presence of DM (p = 0.038), HT (p = 0.003), baseline proteinuria (p = 0.014), and uric acid (p = 0.032) levels and group 2a showed higher rates for each. Progression was more common in patients with DM (p = 0.039), HT (p = 0.003), higher initial and final visit proteinuria (p = 0.014, for both), and higher baseline uric acid levels (p = 0.047). Conclusions. The majority of patients with solitary kidney showed renal damage at presentation. Increased uric acid level is a risk factor for renal damage and progression. For early diagnosis of renal damage and reducing the risk of progression, patients should be referred to a nephrologist as early as possible.

Retrograde intrarenal surgery for urinary stone disease in patients with solitary kidney: A retrospective analysis of the efficacy and safety

OBJECTIVES

To compare outcomes of retrograde intrarenal surgery for urolithiasis between patients with solitary kidneys and patients who have single-side urolithiasis with bilateral kidneys.

METHODS

We retrospectively analyzed outcomes of retrograde intrarenal surgery in solitary kidney patients (group A) carried out during 2007-2014, and in patients with bilateral kidneys with comparable stone burdens (group B). Stone-free status was defined as no residual fragment on computed tomography 1 month later.

RESULTS

There were 19 patients in group A (mean age 62.5 ± 18.4 years, range 14-76 years). The mean stone diameter and burden were 6.0 mm (range 3-24 mm) and 10.42 ± 6.92 mm, respectively. The stone-free rate was 94.7%, and no repeat procedure was required. The glomerular filtration rate tended to rise post-surgery (postoperative day 1: 48.67 ± 15.92 mL/min, 100.2%, P = 0.940; postoperative month 1: 51.32 ± 16.90 mL/min, 105.7%, P = 0.101) compared with preoperative rates. The stone-free rate and surgery time were not significantly different between the two groups, although post-surgical hospitalization time was longer for group A (4.05 vs 3.08 days, P = 0.037). The change in glomerular filtration rate was not significantly different between groups A and B (postoperative day 1: +0.101 vs +0.547 mL/min, respectively, P = 0.857; postoperative month 1: +2.749 vs 3.161 mL/min, respectively, P = 0.882). No significant difference was found in terms of complication rate.

CONCLUSIONS

Retrograde intrarenal surgery in solitary kidney patients is as safe and effective as in bilateral kidney patients.

Compensatory responses to nephron deficiency: adaptive or maladaptive?

Compensatory renal growth is a characteristic adaptation to reduced renal mass that appears to recapitulate the normal pattern of maturation of the kidney during the postnatal period. Hypertrophy of tubules (predominantly the proximal tubule) and glomeruli is accompanied by increased single nephron glomerular filtration rate and tubular reabsorption of sodium. We propose that the very factors, which contribute to the increase in growth and function of the renal tubular system, are, in the long term, the precursors to the development of hypertension in those with a nephron deficit. The increase in single nephron glomerular filtration rate is dependent on multiple factors, including reduced renal vascular resistance associated with an increased influence of nitric oxide, and a rightward shift in the tubuloglomerular feedback curve, both of which contribute to the normal maturation of renal function. The increased influence of nitric oxide appears to contribute to the reduction in tubuloglomerular feedback sensitivity and facilitate the initial increase in glomerular filtration rate. The increased single-nephron filtered load associated with nephron deficiency may promote hypertrophy of the proximal tubule and so increased reabsorption of sodium, and thus a rightward shift in the pressure natriuresis relationship. Normalization of sodium balance can then only occur at the expense of chronically increased arterial pressure. Therefore, alterations/adaptations in tubules and glomeruli in response to nephron deficiency may increase the risk of hypertension and renal disease in the long-term.

Risk factors for perioperative complications in hand-assisted laparoscopic donor nephrectomy

Living donor kidney transplant is the preferred treatment for end-stage renal disease; however, the shortage of kidney donors remains a big problem. One of the major reasons for the shortage of living donors is the risk of potentially serious surgical complications of a procedure in which the donor has no personal medical benefit. Therefore it is important to understand the risk factors for perioperative complications associated with donor nephrectomy. Hand-assisted laparoscopic donor nephrectomy is the preferred approach for kidney procurement in many medical centers. This review gives an overview of the risk factors in donor nephrectomy and more specifically in hand-assisted laparoscopic donor nephrectomy.

Single-centre long-term follow-up of live kidney donors demonstrates preserved kidney function but the necessity of a structured lifelong follow-up

BACKGROUND

The increase of live kidney donation (LKD) demands that we scrutinize its long-term consequences. Socialized medicine in Sweden has allowed us to survey long-term consequences of LKD with a high response rate.

METHODS

Between 1974 and 2008, 455 LKDs were performed; 28 donors were deceased and 14 had moved abroad at the time of the survey. Of the remaining 413, 96% agreed to participate in a retrospective study with laboratory testing and answering a questionnaire.

RESULTS

Mean age at donation was 49 ± 10 years, and the mean time since nephrectomy was 11 ± 7 years (range 1-33). No death was of renal cause. S-creatinine at follow-up was 93 ± 18 μmol/L, 28% had treated hypertension, of whom only 52% had BP <140/90. Eleven per cent had spot microalbuminuria, and 1% were diagnosed with diabetes mellitus. Seventy-one per cent had check-ups at least every second year, but 14% had no check-ups. Eighty per cent would be willing to donate again if it were possible, and only 3% regretted the donation.

CONCLUSION

Renal function is well preserved in the long term after donation, no case of end-stage renal disease was identified, and a large majority of our donors would donate again if it were possible. Although rates of microalbuminuria and hypertension were at expected levels, a significant number of donors demonstrated elevated blood pressure levels and inadequate antihypertensive treatment. A relatively large number of donors did not receive regular check-ups. Both of these issues demonstrate the need for a better-structured lifelong follow-up.

A study to evaluate the effect of ratio of donor kidney weight to recipient body weight on renal graft function

AIM AND OBJECTIVES

To study the effect of the ratio of donor kidney weight (dkw) to recipient body weight (rbw) on short and long term graft function in live donor kidney transplant patients.

MATERIALS AND METHODS

It was a prospective study of 79 live donor kidney transplant recipients. Patients were divided into three groups depending on the ratio of dkw in grams to rbw in kilograms. Serum creatinine in milligrams percent on the day of surgery, 7(th) day, 1 month, 6 months, 1 year, and 3 years after the surgery was recorded and their means compared.

RESULTS

The comparison showed that the decrease in mean creatinine level was more in group three patients as compared with group 2 and one patients at 7 days (1.04,1.44 and 1.59 in group 3,2 and 1 respectively) and 30 days (1.12,1.36 and 1.45 in group 3,2 and 1 respectively), showing that higher dkw/rbw ratio is beneficial with respect to the early graft function. However this decrease was not statistically significant (P value -0.256 and 0.358 respectively on 7(th) and 30(th) day). Furthermore long-term function was not different among these three groups.

CONCLUSION

The ratio of dkw to rbw does not have a significant effect on long-term graft function inspite of an early improvement in the function with increased dkw to rbw ratio.

Low birthweight and risk of albuminuria in living kidney donors

Low birthweight is linked to hypertension, chronic kidney disease and even end-stage renal disease. We hypothesized that living kidney donors born with lower birthweight may be at increased risk of hypertension, albuminuria, or reduced GFR beyond what is typical following uninephrectomy. Two hundred fifty-seven living kidney donors who donated at the University of Minnesota between 1967 and 2005 underwent iohexol GFR and urinary albumin excretion measurements. Predictors of iohexol GFR <60 mL/min/1.73 m(2), albuminuria, and hypertension were examined using logistic regression. Predictors examined include age at GFR measurement, time since donation, BMI, gender, serum creatinine level (at donation and GFR measurement), systolic and diastolic blood pressure, race, and birthweight. The latter was obtained through self-report and verified through birth certificates and family members. Older age, higher BMI, and time from donation were associated with reduced GFR. Older age and higher BMI were also associated with hypertension. Birthweight was not associated with GFR <60 mL/min/1.73 m(2): OR=0.70, 95% CI (0.28, 1.74), p = 0.45 or hypertension: OR=0.92, 95% CI (0.46, 1.84), p = 0.82 but was associated with albuminuria: OR=0.37, 95% CI (0.15, 0.92), p = 0.03. These data further strengthen the link between low birthweight and potential adverse renal outcomes.

Short-term prognosis of living-donor kidney transplantation from hypertensive donors with high-normal albuminuria

BACKGROUND

High-normal albuminuria (HNA) is an independent predictor of cardiovascular risk in the general population. Although hypertensive donor (HTD) candidates with HNA were considered acceptable donors by the Amsterdam Forum 2004, the transplant prognosis of HTDs with HNA has not been determined. Therefore, we investigated the transplant prognosis of HTDs with HNA.

METHODS

We retrospectively analyzed 52 adult living-donor kidney transplants performed at Kagawa University Hospital. HNA was defined as albuminuria of 15 to 30 mg/g Cr. Changes in kidney function of donors and recipients were assessed up to 2 years after transplantation.

RESULTS

Overall, 38 donors were normotensive and 14 were hypertensive. Nine of 14 HTDs exhibited HNA before donation. More HTDs with HNA had arteriosclerotic vasculopathy or glomerulosclerosis than did normotensive donors (NTDs). Hypertension and the degree of albuminuria did not affect the donors' posttransplantation kidney function. The risk of discompensatory changes in kidney function after donation was significantly higher in HTDs with HNA than in NTDs (odds ratio, 10.5; 95% confidence interval, 1.51-72.9; P=0.02). In multivariate analysis, the coexistence of hypertension and HNA was not significantly associated with discompensatory changes after donation (adjusted odds ratio, 6.04; 95% confidence interval, 0.19-192; P=0.31). Recipients of HTDs with HNA had similar allograft survival rates but lower allograft function compared with recipients of NTDs.

CONCLUSIONS

Although further studies are needed to confirm our results, the short-term prognosis of living-donor kidney transplantation was similar between HTDs with HNA and NTDs.

Loss of a kidney during fetal life: long-term consequences and lessons learned

Epidemiological studies reveal that children born with a solitary functioning kidney (SFK) have a greater predisposition to develop renal insufficiency and hypertension in early adulthood. A congenital SFK is present in patients with unilateral renal agenesis or unilateral multicystic kidney dysplasia, leading to both structural and functional adaptations in the remaining kidney, which act to mitigate the reductions in glomerular filtration rate and sodium excretion that would otherwise ensue. To understand the mechanisms underlying the early development of renal insufficiency in children born with a SFK, we established a model of fetal uninephrectomy (uni-x) in sheep, a species that similar to humans complete nephrogenesis before birth. This model results in a 30% reduction in nephron number rather than 50%, due to compensatory nephrogenesis in the remaining kidney. Similar to children with a congenital SFK, uni-x sheep demonstrate a progressive increase in arterial pressure and a loss of renal function with aging. This review summarizes the compensatory changes in renal hemodynamics and tubular sodium handling that drive impairments in renal function and highlights the existence of sex differences in the functional adaptations following the loss of a kidney during fetal life.

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.

The unjustified classification of kidney donors as patients with CKD: critique and recommendations

Unilateral nephrectomy for kidney donation results in loss of about 30% of baseline GFR, leaving some donors with GFR <60 ml/min per 1.73 m(2), the threshold for the diagnosis CKD. This has resulted in insurability problems for some donors. This article reviews the definition of CKD, risks associated with CKD, and large follow-up studies on the vital status and risk of ESRD in kidney donors. It also provides evidence that kidney donors, despite having reduced GFR, are not at increased risk for CKD-associated morbidity and mortality. Epidemiologic studies, most with follow-up <10 years, have shown an association between GFR <60 ml/min per 1.73 m(2) and higher mortality and progression to ESRD. Low GFR in the absence of any other markers for kidney disease, however, conveys attenuated or minimal risk. Of note, studies of long-term kidney donor outcomes (6-45 years) have not shown excess mortality or ESRD. The limitation of the collective evidence is that the increased risks associated with GFR <60 ml/min per 1.73 m(2) were demonstrated in much larger cohorts than those reported for kidney donor outcomes, but donor outcome studies have substantially longer follow-up. On the basis of current findings, kidney donors with low GFR and no other signs of kidney disease should not be classified as having CKD. This is definitely not the reward they deserve, and, more important, the implications of reduced GFR in donors are not associated with unfavorable outcomes.

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.

Pre-emptive kidney transplantation to improve survival in patients with type 1 diabetes and imminent risk of ESRD

Despite significant improvements in the treatment of diabetic nephropathy over the past 20 years, patients with type 1 diabetes are at high risk of developing end-stage renal disease and high mortality once end-stage renal disease develops. Type 1 diabetic patients treated with predialysis (pre-emptive) transplantation have a lower death rate than type 1 diabetic patients treated with dialysis. Living donor kidney transplantation is possible before starting dialysis and is associated with better kidney and patient outcomes as compared with transplantation while on dialysis. In addition, a variety of potential donors can be used, not just young, well-matched family members. Through paired kidney donation, blood group ABO-incompatible transplants and transplants across the barrier of anti-human leukocyte antigen antibodies, diabetic patients can receive living donor kidney transplants even if their intended donor is not a good match for them. Despite these expanded options making living donation possible, only a minority of type 1 diabetic patients receive a pre-emptive kidney transplant. Multiple barriers remain that prevent type 1 diabetic patients from enjoying the reduced risk of death afforded by a pre-emptive kidney transplant, including lack of knowledge by primary care physicians, endocrinologists, and nephrologists; late referral for transplantation; patient and family misconceptions about timing of transplantation; and who can be a donor. The vast majority of type 1 diabetic patients are listed for kidney transplantation after the initiation of dialysis. Of these patients, thousands subsequently receive a live donor kidney transplant. We believe that the appropriate agencies and societies should address the barriers to pre-emptive kidney transplantation through nationwide educational initiatives and study the causes of failure to be transplanted before dialysis initiation.

Modulation of mitochondrial glutathione status and cellular energetics in primary cultures of proximal tubular cells from remnant kidney of uninephrectomized rats

Compensatory renal hypertrophy following reduction in renal mass leads to a hypermetabolic state and increases in basal mitochondrial oxidative stress and susceptibility to several nephrotoxicants. Previous studies provide conflicting data on whether renal mitochondria after reduction in renal mass undergo proliferation or hypertrophy or both. In the present study, our goal was to determine whether mitochondria of hypertrophied kidney undergo hypertrophy or proliferation after uninephrectomy using the uninephrectomized (NPX) rat model. Renal proximal tubular (PT) cells from NPX rats exhibited increased mitochondrial density, membrane potential and protein but no significant difference in mitochondrial DNA, as compared to PT cells from control rats. Our previous studies showed that overexpression of two mitochondrial anion transporters, the dicarboxylate (DIC, Slc25a10) and oxoglutarate (OGC, Slc25a11) carriers, in NRK-52E cells resulted in increased mitochondrial uptake of glutathione (GSH) and protection from chemically induced apoptosis. In the present study, we overexpressed DIC- and OGC-cDNA plasmids to assess their function in renal PT cells after compensatory renal hypertrophy. PT cells from NPX rats that were first preincubated with GSH were protected from cytotoxicity due to the mitochondrial inhibitor antimycin A by overexpression of either of the two mitochondrial GSH transporters. Our present results provide further evidence that compensatory renal hypertrophy is associated primarily with mitochondrial hypertrophy and hyperpolarization and that manipulation of mitochondrial GSH transporters in PT cells of hypertrophied kidney can alter susceptibility to chemically induced injury under appropriate conditions and may be a suitable therapeutic approach.

Potential for deceased donation not optimally exploited: donor action data from six countries

BACKGROUND

Most countries today promote living donation as an alternative to challenge the organ shortage from deceased donors. This seems justifiable provided the potential for deceased donation is optimally exploited.

METHODS

We used the Donor Action (DA) Medical Record Review (MRR) methodology in six countries, to measure whether the potential for heart-beating (HB) deceased donors was adequately converted to donation. Medical record review data were collected from 52,383 patients who died in 605 critical care units in 227 hospitals between January 2007 and December 2009.

RESULTS

On a total of 17,903 ventilated patients aged younger than 76 years and without contraindications to HB donation, 4,855 cases met criteria for brain death (BD) diagnosis and were considered potential HB donors. On average, 24.8±15.9% was not identified as potential donor, 21.9% of identified cases was not referred as such to a procurement team, and in 11.3% of identified cases, no approached was offered with the option to donate. Average consent rates/family approaches or registry consultation was 69.1±14.5%, and average conversion of potential into actual donors was 42.1±7.3%.

CONCLUSIONS

Over 57% of deceased potential donors in the study cohort were missed along the donation pathway because of nonidentification, no referral, no approach of relatives, or objections to donate. In countries with lower donation rates, expectedly more potential donors are missed proportionally. Efforts to increase the organ pool should therefore focus on optimizing clinical practices in deceased organ donation in addition to promoting living organ donation.