APOL1 risk variants enhance podocyte necrosis through compromising lysosomal membrane permeability

Development of higher rates of nondiabetic glomerulosclerosis (GS) in African Americans has been attributed to two coding sequence variants (G1 and G2) in the APOL1 gene. To date, the cellular function and the role of APOL1 variants (Vs) in GS are still unknown. In this study, we examined the effects of overexpressing wild-type (G0) and kidney disease risk variants (G1 and G2) of APOL1 in human podocytes using a lentivirus expression system. Interestingly, G0 inflicted podocyte injury only at a higher concentration; however, G1 and G2 promoted moderate podocyte injury at lower and higher concentrations. APOL1Vs expressing podocytes displayed diffuse distribution of both Lucifer yellow dye and cathepsin L as manifestations of enhanced lysosomal membrane permeability (LMP). Chloroquine attenuated the APOL1Vs-induced increase in podocyte injury, consistent with targeting lysosomes. The chloride channel blocker DIDS prevented APOL1Vs- induced injury, indicating a role for chloride influx in osmotic swelling of lysosomes. Direct exposure of noninfected podocytes with conditioned media from G1- and G2-expressing podocytes also induced injury, suggesting a contributory role of the secreted component of G1 and G2 as well. Adverse host factors (AHFs) such as hydrogen peroxide, hypoxia, TNF-α, and puromycin aminonucleoside augmented APOL1- and APOL1Vs-induced podocyte injury, while the effect of human immunodeficiency virus (HIV) on podocyte injury was overwhelming under conditions of APOLVs expression. We conclude that G0 and G1 and G2 APOL1 variants have the potential to induce podocyte injury in a manner which is further augmented by AHFs, with HIV infection being especially prominent.

Depression and chronic kidney disease: A review for clinicians

OBJECTIVE

To review the recent academic literature surrounding the prevalence, aetiopathology, associations and management of depression in chronic kidney disease (CKD), in order to provide a practical and up-to-date resource for clinicians.

METHODS

We conducted electronic searches of the following databases: MEDLINE, EMBASE and PsycINFO. The main search terms were: depression, mood disorders, depressive disorder, mental illness, in combination with kidney disease, renal insufficiency, dialysis, kidney failure. Separate searches were conducted regarding antidepressant use in CKD.

RESULTS

A number of recent, large and well-conducted studies have confirmed markedly raised rates of depression amongst those with CKD, with meta-analysis suggesting the prevalence of interview-defined depression to be approximately 20%. The interactions between depression and CKD are complex, bidirectional and multifactorial. Depression in CKD has been shown to be associated with multiple poor outcomes, including increased mortality and hospitalisation rates, as well as poorer treatment compliance and quality of life. Clinical evaluation of depression in patients with CKD can be challenging; however, once a diagnosis is made, a range of treatment modalities can be considered.

CONCLUSIONS

Depression is common in CKD and is associated with a significant risk of adverse outcomes. Given the importance of this issue, there is now an urgent need for well-conducted randomised trials of interventions for depression in CKD in order to provide information on the safety and efficacy of treatments.

The effect of chronic kidney disease on total hip arthroplasty

Patients with chronic kidney disease (CKD) undergoing total hip arthroplasty (THA) were evaluated for risk of revision, surgical site infection (SSI), thromboembolic events, mortality and readmission. 20,720 primary TKA cases were included (smaller sample for readmission evaluation, N = 9322). The prevalence of CKD among THA patients was 6.1% (N = 1269). After adjustment for age, gender, race, general health, and diabetes, CKD patients were at 1.4 (95% confidence interval 1.1-1.8) increased risk of readmission within 90 days. The adjusted risks for revision (overall, aseptic, and septic), SSI (deep and superficial), deep vein thrombosis, pulmonary embolism, and mortality (30-day, 90-day, ever) were not significantly different between patients with CKD and those without CKD. However, increased risk for 90-day readmission underscores that CKD patients are a fundamentally different population of patients.

Renoprotective effects of melatonin in young spontaneously hypertensive rats with L-NAME

BACKGROUND

Nitric oxide (NO) deficiency occurs in humans and animals with hypertension and chronic kidney disease (CKD). An inhibitor of NO synthase, N(G)-nitro-l-arginine methyl ester (L-NAME) exacerbates kidney damage in the adult spontaneously hypertensive rat (SHR). We examined whether L-NAME exacerbated hypertensive nephrosclerosis in young SHRs and whether melatonin protects SHRs against kidney damage by restoration of the asymmetric dimethylarginine (ADMA)-NO pathway.

METHODS

Rats aged 4 weeks were randomly assigned into three groups (n = 10 for each group): Group 1 (control), SHRs without treatment; Group 2 (L-NAME), SHRs received L-NAME (80 mg/L) in drinking water; and Group 3 (L-NAME + melatonin), SHRs received L-NAME (80 mg/L) and 0.01% melatonin in drinking water. All rats were sacrificed at 10 weeks of age.

RESULTS

L-NAME exacerbates the elevation of blood pressure, renal dysfunction, and glomerular sclerosis in young SHRs. L-NAME induced an increase of ADMA and a decrease of arginine-to-ADMA ratio in the SHR kidney. Melatonin therapy prevented L-NAME-exacerbated hypertension and nephrosclerosis in young SHRs. In addition, melatonin restored L-NAME-induced reduction of dimethylarginine dimethylaminohydrolase (DDAH; ADMA-metabolizing enzymes) activity in the SHR kidney. Next, melatonin decreased renal ADMA concentrations, increased renal arginine-to-ADMA ratio, and restored NO production in L-NAME-treated young SHRs. Moreover, melatonin reduced the degree of oxidative damaged DNA product, 8-hydroxydeoxyguanosine immunostaining in L-NAME-treated SHR kidney.

CONCLUSION

Our results indicated that L-NAME/SHR is a useful model for hypertensive nephrosclerosis in young rats. The blood pressure-lowering and renoprotective effects of melatonin is due to increases of DDAH activity, decreases of ADMA, and reduction of oxidative stress in L-NAME-treated SHR kidney. Specific therapy targeting the DDAH-ADMA pathway may be a promising approach to slowing chronic kidney disease progression in children.

Iron dosing in kidney disease: inconsistency of evidence and clinical practice

The management of anemia in patients with chronic kidney disease (CKD) is difficult. The availability of erythropoiesis-stimulating agents (ESAs) has increased treatment options for previously transfusion-requiring patients, but the recent evidence of ESA side effects has prompted the search for complementary or alternative approaches. Next to ESA, parenteral iron supplementation is the second main form of anemia treatment. However, as of now, no systematic approach has been proposed to balance the concurrent administration of both agents according to individual patient's needs. Furthermore, the potential risks of excessive iron dosing remain a topic of controversy. How, when and whether to monitor CKD patients for potential iron overload remain to be elucidated. This review addresses the question of risk and benefit of iron administration in CKD, highlights the evidence supporting current practice, provides an overview of standard and potential new markers of iron status and outlines a new pharmacometric approach to physiologically compatible individualized dosing of ESA and iron in CKD patients.

Retinopathy and progression of CKD: The CRIC study

BACKGROUND AND OBJECTIVES

Retinal abnormalities may be associated with changes in the renal vasculature. This study assessed the association between retinopathy and progression of kidney disease in participants of the Chronic Renal Insufficiency Cohort (CRIC) study.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a prospective study in which patients with CKD enrolled in CRIC had nonmydriatic fundus photographs of both eyes. All CRIC participants in six clinical sites in which fundus cameras were deployed were offered participation. Photographs were reviewed at a reading center. The presence and severity of retinopathy and vessel calibers were assessed using standard protocols by graders masked to clinical information. The associations of retinal features with changes in eGFR and the need for RRT (ESRD) were assessed.

RESULTS

Retinal images and renal progression outcomes were obtained from 1852 of the 2605 participants (71.1%) approached. During follow-up (median 2.3 years), 152 participants (8.2%) developed ESRD. Presence and severity of retinopathy at baseline were strongly associated with the risk of subsequent progression to ESRD and reductions in eGFR in unadjusted analyses. For example, participants with retinopathy were 4.4 times (95% confidence interval [95% CI], 3.12 to 6.31) more likely to develop ESRD than those without retinopathy (P<0.001). However, this association was not statistically significant after adjustment for initial eGFR and 24-hour proteinuria. Venular and arteriolar diameter calibers were not associated with ESRD or eGFR decline. The results showed a nonlinear relationship between mean ratio of arteriole/vein calibers and the risk of progression to ESRD; participants within the fourth arteriole/vein ratio quartile were 3.11 times (95% CI, 1.51 to 6.40) more likely to develop ESRD than those in the first quartile (P<0.001).

CONCLUSIONS

The presence and severity of retinopathy were not associated with ESRD and decline in eGFR after taking into account established risk factors.

Does the type of creatinine assay affect creatinine clearance determination?

BACKGROUND

A creatinine clearance (CrCl) is still often requested to estimate the glomerular filtration rate (GFR) in clinical practice. However, the diversity of serum and urine creatinine (Scr, Ucr) assays leads to different CrCl-results which are here compared with each other and with the CKD-EPI eGFR-formula.

METHODS

We collected information on urine volume, Ucr and Scr using Roche's enzymatic (E), compensated Jaffe (CJ) and Jaffe (J) assay for 589 patients. To allow comparison with the CKD-EPI prediction results, CrCl was normalized for body surface area.

RESULTS

Differences between CrCl-E and CrCl-CJ are rather small as opposed to the large differences with CrCl-J. However, two compensating errors in the CrCl-J calculation result in a closer agreement with CKD-EPI eGFR, than between CrCl-CJ or CrCl-E and CKD-EPI eGFR. The explained variance R(2) in all three cases is smaller than 0.66, demonstrating the very large scatter of the data around the regression line.

CONCLUSIONS

CrCl determination is very assay-dependent. Although many clinical labs have switched to ID-GC/MS-standardized assays (E and CJ) for the determination of Scr and Ucr to improve analytical accuracy, the increased deviation of the normalized CrCl from the CKD-EPI prediction illustrates that the use of CrCl remains questionable for clinical practice. When a CrCl is requested, we would even recommend clinical labs who work with compensated Jaffe assays not to compensate the Scr-J value.

The relationship between IL-10 levels and cardiovascular events in patients with CKD

BACKGROUND AND OBJECTIVES

Cardiovascular disease is the leading cause of death in patients with CKD. IL-10 is considered an antiatherosclerotic cytokine. However, previous studies have failed to observe an association between IL-10 and cardiovascular disease in CKD. This study aimed to evaluate whether serum IL-10 levels were associated with the risk of cardiovascular events in CKD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Four hundred three patients with stages 1-5 CKD were followed for a mean of 38 (range=2-42) months for fatal and nonfatal cardiovascular events. IL-10 and IL-6 were measured at baseline together with surrogates of endothelial function (flow-mediated dilatation) and proinflammatory markers (high-sensitivity C-reactive protein and pentraxin-3). The association between IL-10 and flow-mediated dilatation through linear regression analyses was evaluated. The association between IL-10 and the risk of cardiovascular events was assessed with Cox regression analysis.

RESULTS

IL-10, IL-6, high-sensitivity C-reactive protein, and pentraxin-3 levels were higher among participants with lower eGFR. Both fatal (25 of 200 versus 6 of 203 patients) and combined fatal and nonfatal (106 of 200 versus 23 of 203 patients) cardiovascular events were more common in patients with IL-10 concentration above the median. Flow-mediated dilatation was significantly lower in patients with higher serum IL-10 levels, but IL-10 was not associated with flow-mediated dilatation in multivariate analysis. Kaplan-Meier survival curves showed that patients with IL-10 below the median value (<21.5 pg/ml) had higher cumulative survival compared with patients who had IL-10 levels above the median value (log-rank test, P<0.001).

CONCLUSIONS

IL-10 levels increase along with the reduction of kidney function. Higher serum IL-10 levels were associated with the risk of cardiovascular events during follow-up. We speculate that higher IL-10 levels in this context signify an overall proinflammatory milieu.

National trends over 25 years in pediatric kidney transplant outcomes

OBJECTIVE

To investigate changes in pediatric kidney transplant outcomes over time and potential variations in these changes between the early and late posttransplant periods and across subgroups based on recipient, donor, and transplant characteristics.

METHODS

Using multiple logistic regression and multivariable Cox models, graft and patient outcomes were analyzed in 17,446 pediatric kidney-only transplants performed in the United States between 1987 and 2012.

RESULTS

Ten-year patient and graft survival rates were 90.5% and 60.2%, respectively, after transplantation in 2001, compared with 77.6% and 46.8% after transplantation in 1987. Primary nonfunction and delayed graft function occurred in 3.3% and 5.3%, respectively, of transplants performed in 2011, compared with 15.4% and 19.7% of those performed in 1987. Adjusted for recipient, donor, and transplant characteristics, these improvements corresponded to a 5% decreased hazard of graft loss, 5% decreased hazard of death, 10% decreased odds of primary nonfunction, and 5% decreased odds of delayed graft function with each more recent year of transplantation. Graft survival improvements were lower in adolescent and female recipients, those receiving pretransplant dialysis, and those with focal segmental glomerulosclerosis. Patient survival improvements were higher in those with elevated peak panel reactive antibody. Both patient and graft survival improvements were most pronounced in the first posttransplant year.

CONCLUSIONS

Outcomes after pediatric kidney transplantation have improved dramatically over time for all recipient subgroups, especially for highly sensitized recipients. Most improvement in graft and patient survival has come in the first year after transplantation, highlighting the need for continued progress in long-term outcomes.

The pleiotropic effects of the hydroxy-methyl-glutaryl-CoA reductase inhibitors in renal disease

It is well known that statins exert their main effect by inhibiting cholesterol synthesis through the inhibition of the 3-hydroxy-3-methyl-glutaryl-CoA reductase enzyme. The pleiotropic effects of statins, which are independent of their inhibition of cholesterol synthesis, have explained many of the beneficial effects of these drugs in a variety of disorders such as malignancies, infection, and sepsis, as well as in cardiovascular and rheumatologic disorders. However, the role of these drugs in renal disorders remains controversial. In the present review, we examine the most recent findings involving statins and renal disease among different clinical scenarios, including chronic kidney disease, contrast-induced nephropathy, renal injury after coronary artery bypass surgery, and renal transplant patients.

ACE2 deficiency increases NADPH-mediated oxidative stress in the kidney

Abstract Angiotensin-converting enzyme 2 (ACE2) is highly expressed in the kidney and hydrolyzes angiotensin II (Ang II) to Ang(1-7). Since Ang II is a strong activator of oxidative stress, we reasoned that ACE2 could be involved in the regulation of renal oxidative stress by governing the levels of Ang II. We, therefore, assessed levels of oxidative stress in kidney cortex of ACE2 knockout and wild-type littermate mice under baseline conditions. We found multiple markers of increased oxidative stress in ACE2KO mice. NADPH oxidase activity was increased in kidney cortex from ACE2KO mice as compared to WT (227 ± 24% vs.100 ± 19%, P < 0.001). However, kidney catalase and superoxide dismutase activities were not different between groups. Exogenous Ang II was degraded less efficiently by kidneys from ACE2KO mice than WT mice, and administration of an AT1R blocker (losartan 30 mg/kg/day) resulted in normalization of NADPH oxidase activity in the ACE2KO. These findings suggest that an AT1R-dependent mechanism contributes to increased ROS observed in the ACE2KO. This study demonstrates that genetic deficiency of ACE2 activity in mice fosters oxidative stress in the kidney in the absence of overt hypertension and is associated with reduced kidney capacity to hydrolyze Ang II. ACE2KO mice serve as a novel in vivo model to examine the role of overactivity of NADPH oxidase in kidney function.

The kidney research predicament

Research funding from public and private sources has reached an all-time low. Economic conditions, sequestration, and a trend of low award success rates have created an imbalance between the supply of highly qualified research investigators and the availability of critically necessary research dollars. This grim environment continues to hinder the success of established investigators and deter potential investigators from joining the research workforce. Without action and support of innovative science, the future of the US health care system is in jeopardy, and its leadership role in medical research will decrease. This work discusses the effects of the decline in research funding, the plight of kidney research, and the impact of the American Society of Nephrology Grants Program on scientists. The ASN also calls on the entire nephrology community to rejuvenate the research environment, improve the lives of millions of people with kidney disease, and ultimately, find a cure.

Complement factor H gene associations with end-stage kidney disease in African Americans

BACKGROUND

Mutations in the complement factor H gene (CFH) region associate with renal-limited mesangial proliferative forms of glomerulonephritis including IgA nephropathy (IgAN), dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). Lack of kidney biopsies could lead to under diagnosis of CFH-associated end-stage kidney disease (ESKD) in African Americans (AAs), with incorrect attribution to other causes. A prior genome-wide association study in AAs with non-diabetic ESKD implicated an intronic CFH single nucleotide polymorphism (SNP).

METHODS

Thirteen CFH SNPs (8 exonic, 2 synonymous, 2 3'UTR, and the previously associated intronic variant rs379489) were tested for association with common forms of non-diabetic and type 2 diabetes-associated (T2D) ESKD in 3770 AAs (1705 with non-diabetic ESKD, 1305 with T2D-ESKD, 760 controls). Most cases lacked kidney biopsies; those with known IgAN, DDD or C3GN were excluded.

RESULTS

Adjusting for age, gender, ancestry and apolipoprotein L1 gene risk variants, single SNP analyses detected 6 CFH SNPs (5 exonic and the intronic variant) as significantly associated with non-diabetic ESKD (P = 0.002-0.01), three of these SNPs were also associated with T2D-ESKD. Weighted CFH locus-wide Sequence Kernel Association Testing (SKAT) in non-diabetic ESKD (P = 0.00053) and T2D-ESKD (P = 0.047) confirmed significant evidence of association.

CONCLUSIONS

CFH was associated with commonly reported etiologies of ESKD in the AA population. These results suggest that a subset of cases with ESKD clinically ascribed to the effects of hypertension or glomerulosclerosis actually have CFH-related forms of mesangial proliferative glomerulonephritis. Genetic testing may prove useful to identify the causes of renal-limited kidney disease in patients with ESKD who lack renal biopsies.

The eGFR-C study: accuracy of glomerular filtration rate (GFR) estimation using creatinine and cystatin C and albuminuria for monitoring disease progression in patients with stage 3 chronic kidney disease--prospective longitudinal study in a multiethnic population

BACKGROUND

Uncertainty exists regarding the optimal method to estimate glomerular filtration rate (GFR) for disease detection and monitoring. Widely used GFR estimates have not been validated in British ethnic minority populations.

METHODS/DESIGN

Iohexol measured GFR will be the reference against which each estimating equation will be compared. The estimating equations will be based upon serum creatinine and/or cystatin C. The eGFR-C study has 5 components: 1) A prospective longitudinal cohort study of 1300 adults with stage 3 chronic kidney disease followed for 3 years with reference (measured) GFR and test (estimated GFR [eGFR] and urinary albumin-to-creatinine ratio) measurements at baseline and 3 years. Test measurements will also be undertaken every 6 months. The study population will include a representative sample of South-Asians and African-Caribbeans. People with diabetes and proteinuria (ACR ≥30 mg/mmol) will comprise 20-30% of the study cohort.2) A sub-study of patterns of disease progression of 375 people (125 each of Caucasian, Asian and African-Caribbean origin; in each case containing subjects at high and low risk of renal progression). Additional reference GFR measurements will be undertaken after 1 and 2 years to enable a model of disease progression and error to be built.3) A biological variability study to establish reference change values for reference and test measures.4) A modelling study of the performance of monitoring strategies on detecting progression, utilising estimates of accuracy, patterns of disease progression and estimates of measurement error from studies 1), 2) and 3).5) A comprehensive cost database for each diagnostic approach will be developed to enable cost-effectiveness modelling of the optimal strategy.The performance of the estimating equations will be evaluated by assessing bias, precision and accuracy. Data will be modelled as a linear function of time utilising all available (maximum 7) time points compared with the difference between baseline and final reference values. The percentage of participants demonstrating large error with the respective estimating equations will be compared. Predictive value of GFR estimates and albumin-to-creatinine ratio will be compared amongst subjects that do or do not show progressive kidney function decline.

DISCUSSION

The eGFR-C study will provide evidence to inform the optimal GFR estimate to be used in clinical practice.

TRIAL REGISTRATION

ISRCTN42955626.

Incident ESRD among participants in a lead surveillance program

BACKGROUND

Very high levels of lead can cause kidney failure; data about renal effects at lower levels are limited.

STUDY DESIGN

Cohort study, external (vs US population) and internal (by exposure level) comparisons.

SETTINGS & PARTICIPANTS

58,307 men in an occupational surveillance system in 11 US states.

PREDICTOR

Blood lead levels.

OUTCOME

Incident end-stage renal disease determined by matching the cohort with the US Renal Data System (n=302).

MEASUREMENTS

Blood lead categories were 0-<5, 5-<25, 25-<40, 40-51, and >51 μg/dL, defined by highest blood lead test result. One analysis for those with data for race (31% of cohort) and another for the whole cohort after imputing race.

RESULTS

Median follow-up was 12 years. Among those with race information, the end-stage renal disease standardized incidence ratio (SIR; US population as referent) was 1.08 (95% CI, 0.89-1.31) overall. The SIR in the highest blood lead category was 1.47 (95% CI, 0.98-2.11), increasing to 1.56 (95% CI, 1.02-2.29) for those followed up for 5 or more years. For the entire cohort (including those with race imputed), the overall SIR was 0.92 (95% CI, 0.82-1.03), increasing to 1.36 (95% CI, 0.99-1.73) in the highest blood lead category (SIR of 1.43 [95% CI, 1.01-1.85] in those with ≥5 years' follow-up). In internal analyses by Cox regression, rate ratios for those with 5 or more years' follow-up in the entire cohort were 1.0 (0-<5 and 5-<25 μg/dL categories combined) and 0.92, 1.08, and 1.96 for the 25-<40, 40-51, and >51 μg/dL categories, respectively (P for trend=0.003). The effect of lead was strongest in nonwhites.

LIMITATIONS

Lack of detailed work history, reliance on only a few blood lead tests per person to estimate level of exposure, lack of clinical data at time of exposure.

CONCLUSIONS

Data suggest that current US occupational limits on blood lead levels may need to be strengthened to avoid kidney disease.

Adiponectin effects on the kidney

Adiponectin is a 30-kDa polypeptide secreted primarily by adipose tissue and plays a key role in kidney disease. In obesity, reduced adiponectin levels are associated with insulin resistance, cardiovascular disease and obesity related kidney disease. The latter includes microalbuminuria, glomerulomegaly, overt proteinuria and focal segmental glomerulosclerosis. Adiponectin levels in type 2 diabetics also negatively correlate with early features of nephropathy. However, in patients with established chronic kidney disease, adiponectin levels are elevated and positively predict progression of disease. The mechanism of action of adiponectin in the kidney appears to be related to AMPK activation and NADPH oxidase. Further studies are needed to elucidate this pathway and investigate the role of potential targets of adiponectin-AMPK-Nox pathway for CKD as obesity-related CKD is increasing worldwide.

Incident ESRD and treatment-resistant hypertension: the reasons for geographic and racial differences in stroke (REGARDS) study

BACKGROUND

Studies suggest that treatment-resistant hypertension is common and increasing in prevalence among US adults. Although hypertension is a risk factor for end-stage renal disease (ESRD), few data are available for the association between treatment-resistant hypertension and ESRD risk.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

We analyzed data from 9,974 REGARDS (Reasons for Geographic and Racial Differences in Stroke) Study participants treated for hypertension without ESRD at baseline.

PREDICTOR

Treatment-resistant hypertension was defined as uncontrolled blood pressure (BP) with concurrent use of 3 antihypertensive medication classes including a diuretic or use of 4 or more antihypertensive medication classes including a diuretic regardless of BP.

OUTCOME

Incident ESRD was identified by linkage of REGARDS Study participants with the US Renal Data System.

MEASUREMENTS

During a baseline in-home study visit, BP was measured twice and classes of antihypertensive medication being taken were determined by pill bottle inspection.

RESULTS

During a median follow-up of 6.4 years, there were 152 incident cases of ESRD (110 ESRD cases among 2,147 with treatment-resistant hypertension and 42 ESRD cases among 7,827 without treatment-resistant hypertension). The incidence of ESRD per 1,000 person-years for hypertensive participants with and without treatment-resistant hypertension was 8.86 (95% CI, 7.35-10.68) and 0.88 (95% CI, 0.65-1.19), respectively. After multivariable adjustment, the HR for ESRD comparing hypertensive participants with versus without treatment-resistant hypertension was 6.32 (95% CI, 4.30-9.30). Of participants who developed incident ESRD during follow-up, 72% had treatment-resistant hypertension at baseline.

LIMITATIONS

BP, estimated glomerular filtration rate, and albuminuria assessed at a single time.

CONCLUSIONS

Individuals with treatment-resistant hypertension are at increased risk for ESRD. Appropriate clinical management strategies are needed to treat treatment-resistant hypertension in order to preserve kidney function in this high-risk group.

Podocyte pathology and nephropathy - sphingolipids in glomerular diseases

Sphingolipids are components of the lipid rafts in plasma membranes, which are important for proper function of podocytes, a key element of the glomerular filtration barrier. Research revealed an essential role of sphingolipids and sphingolipid metabolites in glomerular disorders of genetic and non-genetic origin. The discovery that glucocerebrosides accumulate in Gaucher disease in glomerular cells and are associated with clinical proteinuria initiated intensive research into the function of other sphingolipids in glomerular disorders. The accumulation of sphingolipids in other genetic diseases including Tay-Sachs, Sandhoff, Fabry, hereditary inclusion body myopathy 2, Niemann-Pick, and nephrotic syndrome of the Finnish type and its implications with respect to glomerular pathology will be discussed. Similarly, sphingolipid accumulation occurs in glomerular diseases of non-genetic origin including diabetic kidney disease (DKD), HIV-associated nephropathy, focal segmental glomerulosclerosis (FSGS), and lupus nephritis. Sphingomyelin metabolites, such as ceramide, sphingosine, and sphingosine-1-phosphate have also gained tremendous interest. We recently described that sphingomyelin phosphodiesterase acid-like 3b (SMPDL3b) is expressed in podocytes where it modulates acid sphingomyelinase activity and acts as a master modulator of danger signaling. Decreased SMPDL3b expression in post-reperfusion kidney biopsies from transplant recipients with idiopathic FSGS correlates with the recurrence of proteinuria in patients and in experimental models of xenotransplantation. Increased SMPDL3b expression is associated with DKD. The consequences of differential SMPDL3b expression in podocytes in these diseases with respect to their pathogenesis will be discussed. Finally, the role of sphingolipids in the formation of lipid rafts in podocytes and their contribution to the maintenance of a functional slit diaphragm in the glomerulus will be discussed.

Metabolism, energetics, and lipid biology in the podocyte - cellular cholesterol-mediated glomerular injury

Chronic kidney disease (CKD) is associated with a high risk of death. Dyslipidemia is commonly observed in patients with CKD and is accompanied by a decrease in plasma high-density lipoprotein, and an increase in plasma triglyceride-rich lipoproteins and oxidized lipids. The observation that statins may decrease albuminuria but do not stop the progression of CKD indicates that pathways other than the cholesterol synthesis contribute to cholesterol accumulation in the kidneys of patients with CKD. Recently, it has become clear that increased lipid influx and impaired reverse cholesterol transport can promote glomerulosclerosis, and tubulointerstitial damage. Lipid-rafts are cholesterol-rich membrane domains with important functions in regulating membrane fluidity, membrane protein trafficking, and in the assembly of signaling molecules. In podocytes, which are specialized cells of the glomerulus, they contribute to the spatial organization of the slit diaphragm (SD) under physiological and pathological conditions. The discovery that podocyte-specific proteins such as podocin can bind and recruit cholesterol contributing to the formation of the SD underlines the importance of cholesterol homeostasis in podocytes and suggests cholesterol as an important regulator in the development of proteinuric kidney disease. Cellular cholesterol accumulation due to increased synthesis, influx, or decreased efflux is an emerging concept in podocyte biology. This review will focus on the role of cellular cholesterol accumulation in the pathogenesis of kidney diseases with a focus on glomerular diseases.

Elevated human chorionic gonadotropin levels in patients with chronic kidney disease: Case series and review of literature

Women are often subjected to serum human chorionic gonadotropin (HCG) testing prior to diagnostic and therapeutic interventions. A positive result leads to further testing to rule out pregnancy and avoid possible fetal teratogenicity. The impact of chronic kidney disease (CKD) on HCG testing has not been studied. We report a series of 5 women out of 62 with CKD, who had a positive HCG test on routine pre-transplant screening at a single transplant center. We analyzed their case records retrospectively. Despite aggressive investigation, their elevated HCG levels remained unexplained. The positive test contributed to delays in transplantation and increased overall cost of treatment.

Management of patients with risk factors

This review addresses concomitant diseases and risk factors in patients treated for diseases of the ears, nose and throat in outpatient and hospital services. Besides heart disease, lung disease, liver disease and kidney disease, this article also covers disorders of coagulation (including therapy with new oral anticoagulants) and electrolyte imbalance. Special attention is paid to the prophylaxis, diagnosis and treatment of perioperative delirium. It is also intended to help optimise the preparation for surgical procedures and pharmacotherapy during the hospital stay.

Haemoglobinuria is associated with chronic kidney disease and its progression in patients with sickle cell anaemia

To evaluate the association between haemoglobinuria and chronic kidney disease (CKD) in sickle cell anaemia (SCA), we analysed 356 adult haemoglobin SS or Sβ(o) thalassaemia patients from the University of Illinois at Chicago (UIC) and 439 from the multi-centre Walk-Treatment of Pulmonary Hypertension and Sickle Cell Disease with Sildenafil Therapy (Walk-PHaSST) cohort. CKD was classified according to National Kidney Foundation Kidney Disease Outcomes Quality Initiatives guidelines. Haemoglobinuria, defined as positive haem on urine dipstick with absent red blood cells on microscopy, was confirmed by enzyme-linked immunosorbent assay in a subset of patients. The prevalence of CKD was 58% in the UIC cohort and 54% in the Walk-PHaSST cohort, and haemoglobinuria was observed in 36% and 20% of the patients, respectively. Pathway analysis in both cohorts indicated an independent association of lactate dehydrogenase with haemoglobinuria and, in turn, independent associations of haemoglobinuria and age with CKD (P < 0·0001). After a median of 32 months of follow-up in the UIC cohort, haemoglobinuria was associated with progression of CKD [halving of estimated glomerular filtration rate or requirement for dialysis; Hazard ratio (HR) 13·9, 95% confidence interval (CI) 1·7-113·2, P = 0·0012] and increasing albuminuria (HR 3·1, 95% CI: 1·3-7·7; logrank P = 0·0035). In conclusion haemoglobinuria is common in SCA and is associated with CKD, consistent with a role for intravascular haemolysis in the pathogenesis of renal dysfunction in SCA.

Population ancestry and genetic risk for diabetes and kidney, cardiovascular, and bone disease: modifiable environmental factors may produce the cures

Variable rates of disease observed between members of different continental population groups may be mediated by inherited factors, environmental exposures, or their combination. This article provides evidence in support of differential allele frequency distributions that underlie the higher rates of nondiabetic kidney disease in the focal segmental glomerulosclerosis spectrum of disease and lower rates of coronary artery calcified atherosclerotic plaque and osteoporosis in populations of African ancestry. With recognition that these and other common complex diseases are affected by biological factors comes the realization that targeted manipulation of environmental exposures and pharmacologic treatments will have different effects based on genotype. The present era of precision medicine will couple one's genetic makeup with specific therapies to reduce rates of disease based on the presence of disease-specific alleles.

Hypertension and chronic kidney disease in Turkey

Worldwide, both hypertension and chronic kidney disease are major public health problems, due to their epidemic proportions and their association with high cardiovascular mortality. In 2003, the first Prevalence, awareness, treatment, and control of hypertension in Turkey (the PatenT) study was conducted in a nationally representative population (n=4910) by the Turkish Society of Hypertension and Renal Diseases, and showed that overall age- and sex-adjusted prevalence of hypertension in Turkey was 31.8%. The PatenT study also reported that overall awareness (40.7%), treatment (31.1%), and control rates (8.1%) of hypertension were strikingly low. Only 20.7% of the patients who were aware of their hypertension and receiving treatment had their blood pressure controlled to <140/90 mm Hg. In the Chronic Renal Disease in Turkey (CREDIT) study (n=10,748), the overall prevalence of chronic kidney (including all stages) disease was 15.7% and increased with advancing age. In the same population, the prevalence of hypertension, diabetes mellitus, dyslipidemia, obesity, and metabolic syndrome were reported as 32.7%, 12.7%, 76.3%, 20.1%, and 31.3%, respectively. The prevalence and awareness of hypertension in CREDIT population was 32.7% and 48.6%, respectively. According to the data obtained from national surveys, the prevalence of hypertension and chronic kidney disease in Turkey is alarmingly high. To improve prevention, early diagnosis, and treatment of these major public health problems, appropriate health strategies should be implemented by the government, together with medical societies, non-governmental organizations, industry, health-care providers, and academia.

Coherence: a novel nonpharmacological modality for lowering blood pressure in hypertensive patients

This study examined the efficacy of teaching emotional self-regulation techniques supported by heart rhythm coherence training (emWave Personal Stress Reliever) as a means to quickly lower blood pressure (BP) in patients diagnosed with hypertension. Previous studies have demonstrated systemic reductions in BP in both high stress populations and patients diagnosed with hypertension using this approach, but to the best of our knowledge, an investigation of their ability to produce immediate reductions in BP had not been published in the medical literature. The study was a randomized controlled design with 62 hypertensive participants who were divided into three groups. Group 1 was taking hypertensive medication, was taught self-regulation technique, and used heart rate variability coherence (HRVC) training devices. Group 2 was not yet taking medication and was trained in the same intervention. Group 3 was taking hypertensive medication but did not receive the intervention and was instructed to relax between the BP assessments. An analysis of covariates was conducted to compare the effectiveness of three different interventions on reducing the participants' BP. The use of the self-regulation technique and the HRVC-monitoring device was associated with a significantly greater reduction in mean arterial pressure in the two groups who used the intervention as compared with the relaxation-plus-medication group. Additionally, the group not taking medication that used the intervention also had a significantly greater reduction in systolic BP than the relaxation- plus-medication group. These results suggest that self-regulation techniques that incorporate the intentional generation of positive emotions to facilitate a shift into the psychophysiological coherence state are an effective approach to lowering BP. This approach to reducing BP should be considered a simple and effective approach that can easily be taught to patients to quickly lower their BP in stressful situations. The technique should be especially useful when hypertensive patients are experiencing stressful emotions or reactions to stressors. It is possible that the BP reductions associated with the use of the technique leads to a change in the physiological set-point for homeostatic regulation of BP. Further studies should examine if large scale implementations of such heart-based coherence techniques could have a significant impact on reducing risk of mortality and morbidity in hypertensive patients.

A pilot trial of a computerized renal template note to improve resident knowledge and documentation of kidney disease

BACKGROUND

Kidney disease is under-documented in physician notes. The use of template-guided notes may improve physician recognition of kidney disease early in training.

OBJECTIVE

The objective of this study was to determine whether a computerized inpatient renal template note with clinical decision support improves resident knowledge and documentation of kidney disease.

METHODS

In this prospective study, first year medical residents were encouraged to use the renal template note for documentation over a one-month period. The renal template note included an option for classification of acute kidney injury (AKI) and chronic kidney disease (CKD) categories with a link to standard classifications. Pre- and post-knowledge of AKI and CKD categories was tested with a quiz and surveys of resident experience with the intervention were conducted. Appropriate AKI and/or CKD classification was determined in 100 renal template notes and 112 comparable historical internal medicine resident progress notes from approximately one year prior.

RESULTS

2,435 inpatient encounters amongst 15 residents who participated were documented using the renal template note. A significantly higher percent of residents correctly staged earlier stage CKD (CKD3) using the renal template note compared to historical notes (9/46 vs. 0/33, p<0.01). Documentation of AKI and more advanced CKD stages (CKD4 and 5) did not improve. Knowledge based on quiz scores increased modestly but was not significant. The renal template note was well received by residents and was perceived as helping improve knowledge and documentation of kidney disease.

CONCLUSION

The renal template note significantly improved staging of earlier stage CKD (CKD3) with a modest but non-significant improvement in resident knowledge. Given the importance of early recognition and treatment of CKD, future studies should focus on teaching early recognition using template notes with supplemental educational interventions.

Massive analysis of cDNA Ends (MACE) and miRNA expression profiling identifies proatherogenic pathways in chronic kidney disease

Epigenetic dysregulation contributes to the high cardiovascular disease burden in chronic kidney disease (CKD) patients. Although microRNAs (miRNAs) are central epigenetic regulators, which substantially affect the development and progression of cardiovascular disease (CVD), no data on miRNA dysregulation in CKD-associated CVD are available until now. We now performed high-throughput miRNA sequencing of peripheral blood mononuclear cells from ten clinically stable hemodialysis (HD) patients and ten healthy controls, which allowed us to identify 182 differentially expressed miRNAs (e.g., miR-21, miR-26b, miR-146b, miR-155). To test biological relevance, we aimed to connect miRNA dysregulation to differential gene expression. Genome-wide gene expression profiling by MACE (Massive Analysis of cDNA Ends) identified 80 genes to be differentially expressed between HD patients and controls, which could be linked to cardiovascular disease (e.g., KLF6, DUSP6, KLF4), to infection / immune disease (e.g., ZFP36, SOCS3, JUND), and to distinct proatherogenic pathways such as the Toll-like receptor signaling pathway (e.g., IL1B, MYD88, TICAM2), the MAPK signaling pathway (e.g., DUSP1, FOS, HSPA1A), and the chemokine signaling pathway (e.g., RHOA, PAK1, CXCL5). Formal interaction network analysis proved biological relevance of miRNA dysregulation, as 68 differentially expressed miRNAs could be connected to 47 reciprocally expressed target genes. Our study is the first comprehensive miRNA analysis in CKD that links dysregulated miRNA expression with differential expression of genes connected to inflammation and CVD. After recent animal data suggested that targeting miRNAs is beneficial in experimental CVD, our data may now spur further research in the field of CKD-associated human CVD.

ACE2 alterations in kidney disease

Angiotensin-converting enzyme 2 (ACE2) is a monocarboxypeptidase that degrades angiotensin (Ang) II to Ang-(1-7). ACE2 is highly expressed within the kidneys, it is largely localized in tubular epithelial cells and less prominently in glomerular epithelial cells and in the renal vasculature. ACE2 activity has been shown to be altered in diabetic kidney disease, hypertensive renal disease and in different models of kidney injury. There is often a dissociation between tubular and glomerular ACE2 expression, particularly in diabetic kidney disease where ACE2 expression is increased at the tubular level but decreased at the glomerular level. In this review, we will discuss alterations in circulating and renal ACE2 recently described in different renal pathologies and disease models as well as their possible significance.

Distribution of and factors contributing to chronic kidney disease in a middle-aged working population

OBJECTIVES

To clarify the distribution of chronic kidney disease (CKD) and the factors contributing to its development and progression in middle-aged Japanese workers/employees.

METHODS

This was a retrospective study involving 3,964 men and 2,698 women aged 35-64 years in 2009 who had been followed-up until 2003. Data on proteinuria determined with a dipstick and glomerular filtration rate estimated from serum creatinine concentration (eGFR) were collected in the annual health check-ups.

RESULTS

Proteinuria was detected in 2.9 and 1.1 % of the men and women, respectively, and total CKD was detected in 16.0 and 16.1 % of the men and women respectively. Moderate or severe CKD associated a high risk of cardiovascular diseases and end-stage kidney disease was found mostly in the male subjects [2.0 (men) vs. 0.6 % (women)]. High-risk CKD was found in 3.3 % of the men aged 55-64 years. A body mass index (BMI) of ≥30, hypertension, diabetes mellitus (DM), current smoking and some job types were independently related to the development of proteinuria, while age, BMI, hypertriglyceridemia, and job types were related to total CKD. The development of high-risk CKD was related to preceding mild CKD signs of reduced eGFR and proteinuria as well as to hypertension, DM, smoking, and job type.

CONCLUSIONS

Chronic kidney disease was found in 16 % of middle-aged workers with an equal prevalence in both sexes, while high-risk CKD was found mostly in men, of whom 3.3 % were aged 55-64 years. Obesity, hypertension, DM, smoking and some job types were related to the development and progression of CKD.

Effect of P2X4 and P2X7 receptor antagonism on the pressure diuresis relationship in rats

Reduced glomerular filtration, hypertension and renal microvascular injury are hallmarks of chronic kidney disease, which has a global prevalence of ~10%. We have shown previously that the Fischer (F344) rat has lower GFR than the Lewis rat, and is more susceptible to renal injury induced by hypertension. In the early stages this injury is limited to the pre-glomerular vasculature. We hypothesized that poor renal hemodynamic function and vulnerability to vascular injury are causally linked and genetically determined. In the present study, normotensive F344 rats had a blunted pressure diuresis relationship, compared with Lewis rats. A kidney microarray was then interrogated using the Endeavour enrichment tool to rank candidate genes for impaired blood pressure control. Two novel candidate genes, P2rx7 and P2rx4, were identified, having a 7− and 3− fold increased expression in F344 rats. Immunohistochemistry localized P2X₄ and P2X₇ receptor expression to the endothelium of the pre-glomerular vasculature. Expression of both receptors was also found in the renal tubule; however there was no difference in expression profile between strains. Brilliant Blue G (BBG), a relatively selective P2X₇ antagonist suitable for use in vivo, was administered to both rat strains. In Lewis rats, BBG had no effect on blood pressure, but increased renal vascular resistance, consistent with inhibition of some basal vasodilatory tone. In F344 rats BBG caused a significant reduction in blood pressure and a decrease in renal vascular resistance, suggesting that P2X₇ receptor activation may enhance vasoconstrictor tone in this rat strain. BBG also reduced the pressure diuresis threshold in F344 rats, but did not alter its slope. These preliminary findings suggest a physiological and potential pathophysiological role for P2X₇ in controlling renal and/or systemic vascular function, which could in turn affect susceptibility to hypertension-related kidney damage.

Gene-gene interactions in APOL1-associated nephropathy

BACKGROUND

Two APOL1 nephropathy variants confer substantial risk for non-diabetic end-stage kidney disease (ESKD) in African Americans (AAs). Since not all genetically high-risk individuals develop ESKD, modifying factors likely contribute. Forty-two potentially interactive single nucleotide polymorphisms (SNPs) from a genome-wide association study in non-diabetic ESKD were tested for interaction with APOL1 to identify genes modifying risk for non-diabetic nephropathy.

METHODS

SNPs were examined in an expanded sample of 1367 AA non-diabetic ESKD cases and 1504 AA non-nephropathy controls, with validation in an independent family-based cohort containing 608 first-degree relatives of index cases with non-diabetic ESKD. Logistic regression and mixed models were fitted to test for interaction effects with APOL1 on ESKD, estimated kidney function and albuminuria.

RESULTS

Among ESKD samples, 14 of 42 SNPs demonstrated suggestive APOL1 interaction with P-values <0.05. After Bonferroni correction, significant interactions with APOL1 were seen with SNPs in podocin (rs16854341; NPHS2, P = 8.0 × 10(-4)), in SDCCAG8 (rs2802723; P = 5.0 × 10(-4)) and near BMP4 (rs8014363; P = 1.0 × 10(-3)); with trends for ENOX1 (rs9533534; P = 2.2 × 10(-3)) and near TRIB1 (rs4457349; P = 5.7 × 10(-3)). The minor allele in NPHS2 markedly changed the APOL1-ESKD association odds ratio (OR) from 7.03 to 1.76 (∼50% reduction in effect per copy of the minor allele), rs2802723 changed the OR from 5.1 to 10.5, and rs8014363 increased the OR from 4.8 to 9.5. NPHS2 (P = 0.05) and SDCCAG8 (P = 0.03) SNPs demonstrated APOL1 interaction with albuminuria in independent family-based samples.

CONCLUSIONS

Variants in NPHS2, SDCCAG8 and near BMP4 appear to interact with APOL1 to modulate the risk for non-diabetic ESKD in AAs.

Concentrated fish oil (Lovaza(R)) extends lifespan and attenuates kidney disease in lupus-prone short-lived (NZBxNZW)F1 mice

A growing number of reports indicate that anti-inflammatory actions of fish oil (FO) are beneficial against systemic lupus erythematosus (SLE). However, the majority of pre-clinical studies were performed using 5-20% FO, which is higher than the clinically relevant dose for lupus patients. The present study was performed in order to determine the effective low dose of FDA-approved concentrated FO (Lovaza®) compared to the commonly used FO-18/12 (18-Eicosapentaenoic acid [EPA]/12-Docosahexaenoic acid [DHA]). We examined the dose-dependent response of Lovaza® (1% and 4%) on an SLE mouse strain (NZBxNZW)F1 and compared the same with 1% and 4% placebo, as well as 4% FO-18/12, maintaining standard chow as the control. Results show for the first time that 1% Lovaza® extends maximal lifespan (517 d) and 4% Lovaza® significantly extends both the median (502 d) and maximal (600 d) life span of (NZBxNZW)F1 mice. In contrast, FO-18/12 extends only median lifespan (410 d) compared to standard chow diet (301 d). Additionally, 4% Lovaza® significantly decreased anti-dsDNA antibodies, reduced glomerulonephritis and attenuated lipopolysaccharide-induced pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in splenocytes compared to placebo. 4% Lovaza® was also shown to reduce the expression of inflammatory cytokines, including IL-1β, IL-6 and TNF-α, while increasing renal anti-oxidant enzymes in comparison to placebo. Notably, NFκB activation and p65 nuclear translocation were lowered by 4% Lovaza® compared to placebo. These data indicate that 1% Lovaza® is beneficial, but 4% Lovaza® is more effective in suppressing glomerulonephritis and extending life span of SLE-prone short-lived mice, possibly via reducing inflammation signaling and modulating oxidative stress.

Human immunodeficiency virus infection and kidney disease

Since the introduction of highly active antiretroviral therapy (HAART) in 1996, mortality in patients with human immunodeficiency virus (HIV) infection has decreased markedly. As a result, morbidity from other chronic conditions such as kidney, liver and heart disease is increasing. This is in part as a natural consequence of ageing, and in part due to the higher risk of solid organ failure in these individuals. This higher risk is related to the co-morbidities associated with HIV infection and to the metabolic consequences of drug therapy. Kidney disease is an important cause of morbidity and mortality in patients with HIV infection and encompasses a range of clinical presentations including acute kidney injury, chronic kidney disease (CKD), and end-stage kidney disease. Black race is the most important predictor of kidney disease in HIV-infected persons due to both genetic and modifiable causes. HIVassociated nephropathy (HIVAN) is caused by viral infection of the renal epithelium and, although decreasing in incidence, remains the most common cause of CKD in HIV-infected persons. In addition to HIVAN, a wide spectrum of other histopathological presentations, many of which are immune complex-mediated, is increasingly recognised. Clinicians who treat these patients should be aware of the nephrotoxic potential of several commonly used medications, particularly antiviral agents, and also the need to dose-adjust medication in renal impairment. The increased life expectancy of patients with HIV and end-stage kidney disease has meant that kidney transplantation is increasingly an option. Results from carefully conducted prospective studies are promising, at least in the short term.

Matrix metalloproteinases, atherosclerosis, proteinuria and kidney disease: Linkage-based approaches

Matrix metalloproteinases (MMPs) are important enzymes of extracellular matrix (ECM) degradation for creating the cellular environments required during development and morphogenesis. MMPs, collectively called matrixins, regulate also the biological activity of non matrix substrates such as cytokines, chemokines, receptors, growth factors and cell adhesion molecules. Enzymatic activity is regulated at multiple levels. Endogenous specific inhibitors of metalloproteinases (TIMPs) participate in controlling the local activities of MMPs in tissues. The pathological effects of MMPs and TIMPs are involved in cardiovascular disease (CVD) processes, including atherosclerosis and in a number of renal pathophysiologic alterations, both acute and chronic, linking them to acute kidney injury, glomerulosclerosis and tubulointerstitial fibrosis. This review presents an overview of the place of MMPs in atherosclerosis, proteinuria and kidney disease as a subject of considerable interest, given the differentiated and ambiguous role of MMPs in the progression of these diseases.

The effect of bariatric surgery on renal function and disease: a focus on outcomes and inflammation

Renal dysfunction and disease, including hyperfiltration, proteinuria and hypofiltration, are commonly associated with obesity. Diabetic kidney disease is also common in obese cohorts. Weight loss interventions, including bariatric surgery, can effectively reduce weight and improve renal outcomes. Some of this effect may be due to the remission of Type 2 diabetes and hypertension. However, other mechanisms, including the resolution of inflammatory processes, may also contribute. The effect of bariatric surgery on renal function has only recently become a focus of particular investigation. In this study, we will review the effects of bariatric surgery on obesity-associated kidney disease. We will discuss the pitfalls in assessing renal function in obese cohorts and will examine the effect of bariatric surgery on renal function and urinary protein excretion using different mechanisms. We will give particular attention to the evidence for bariatric surgery in cohorts with established renal disease and suggest future directions. In particular, we will outline the evidence for inflammation as an important therapeutic target, and the emerging medical therapies being considered to exploit this target in obesity- and diabetes-related kidney disease.

A review of cardiovascular and renal function monitoring: a consideration of older adults with HIV

The prevalence of human immunodeficiency virus (HIV) infection in older and elderly adults is significant worldwide. This population poses new challenges and opportunities in the management of HIV. In addition to the risks affecting HIV patients of all ages, including risk of opportunistic infection and medication resistance, age-related changes in physiology, higher comorbidity burdens, increased use of medications, and potential adverse drug reactions to HIV medications all factor into the care of older adults with HIV. The risk and progression of cardiovascular and renal comorbidities may be higher in the older adult HIV population and in patients taking specific HIV medications. Understanding these risks is essential when managing a new type of patient: the older adult with HIV.

Evolution of glomerular filtration rate in HIV-infected, HIV-HBV-coinfected and HBV-infected patients receiving tenofovir disoproxil fumarate

We aimed to compare the evolution of estimated glomerular filtration rate (eGFR) in HIV-, HIV-HBV- and HBV-infected patients treated with tenofovir disoproxil fumarate (TDF). Three groups of patients receiving TDF > 12 months were recruited: 194 HIV-infected patients, 85 HIV-HBV-coinfected patients and 50 HBV-infected patients. eGFR was estimated using the Modification of the Diet in Renal Disease (MDRD) equation. Multivariate regression models were constructed to estimate factors associated with eGFR decrease from baseline. A total of 329 patients were studied. Median follow-up was 2.7 years. Median eGFR decrease was -4.9 (-16.6 to +7.2) mL/min/1.73 m(2) . After multivariate stepwise regression analysis, age (P = 0.0002), non-African origin (P < 0.0001), baseline eGFR (P < 0.0001) and TDF duration (P = 0.02) were associated with eGFR decrease in the whole population, while hypertension, diabetes and type of infection were not. Age (P < 0.0001), non-African origin (P = 0.0004), baseline eGFR (P < 0.0001) and TDF duration (P = 0.007) remained associated with eGFR decline in HIV and HIV-HBV-infected patients, while other variables including HIV risk factor, CDC stage, CD4 and HIV-RNA levels were not. Age (P = 0.03), non-African origin (P = 0.004), baseline eGFR (P < 0.0001) and baseline HBV-DNA > 2000 IU/mL (P = 0.04) were associated with eGFR decline in HBV and HIV-HBV-infected patients, while other variables including HBV risk factor and fibrosis stage were not. Estimated glomerular filtration rate decline under TDF therapy appears mainly associated with older age, non-African origin, higher baseline eGFR and longer TDF administration but not with the type of viral infection. Regular follow-up of renal function, especially tubular function is recommended during TDF therapy.

Metformin therapy and kidney disease: a review of guidelines and proposals for metformin withdrawal around the world

OBJECTIVE

We compared and contrasted guidelines on metformin treatment in patients with chronic kidney disease (CKD) around the world, with the aim of helping physicians to refine their analysis of the available evidence before deciding whether to continue or withdraw this drug.

METHODS

We performed a systematic research for metformin contraindications in: (i) official documents from the world's 20 most populated countries and the 20 most scientifically productive countries in the field of diabetology and (ii) publications referenced in electronic databases from 1990 onwards.

RESULTS

We identified three international guidelines, 31 national guidelines, and 20 proposals in the scientific literature. The criteria for metformin withdrawal were (i) mainly qualitative in the most populated countries; (ii) mainly quantitative in the most scientifically productive countries (with, in all cases, a suggested threshold for withdrawing metformin); and (iii) quantitative in all, but one of the literature proposals, with a threshold for withdrawal in most cases (n = 17) and/or adjustment of the metformin dose as a function of renal status (n = 8). There was a good degree of consensus on serum creatinine thresholds; whereas guidelines based on estimated glomerular filtration rate thresholds varied from 60 mL/minute/1.73 m(2) up to stage 5 CKD. Only one of the proposals has been tested in a prospective study.

CONCLUSIONS

In general, proposals for continuing or stopping metformin therapy in CKD involve a threshold (whether based on serum creatinine or estimated glomerular filtration rate) rather than the dose adjustment as a function of renal status (in stable patients) performed for other drugs excreted by the kidney.

Uric acid lowering to prevent kidney function loss in diabetes: the preventing early renal function loss (PERL) allopurinol study

Diabetic kidney disease causes significant morbidity and mortality among people with type 1 diabetes (T1D). Intensive glucose and blood pressure control have thus far failed to adequately curb this problem and therefore a major need for novel treatment approaches exists. Multiple observations link serum uric acid levels to kidney disease development and progression in diabetes and strongly argue that uric acid lowering should be tested as one such novel intervention. A pilot of such a trial, using allopurinol, is currently being conducted by the Preventing Early Renal Function Loss (PERL) Consortium. Although the PERL trial targets T1D individuals at highest risk of kidney function decline, the use of allopurinol as a renoprotective agent may also be relevant to a larger segment of the population with diabetes. As allopurinol is inexpensive and safe, it could be cost-effective even for relatively low-risk patients, pending the completion of appropriate trials at earlier stages.

Changes in the histological spectrum of glomerular diseases in the past 16 years in the North-Eastern region of Romania

BACKGROUND

The aim of this study was to describe the findings of renal biopsies from a large nephrology center in Iasi, Romania, performed between 2005 and 2010. We compared these findings with our previous ones, from 1995 to 2004, as well as with similar reports.

METHODS

We studied retrospectively 239 renal biopsies. The indications for renal biopsy were categorized into: nephrotic syndrome, acute nephritic syndrome, asymptomatic urinary abnormalities, acute kidney injury, and chronic kidney disease of unknown etiology.

RESULTS

During the past 16 years, a gradual increase in the annual number of renal biopsies/per million population (p.m.p.)/year was observed, although this incidence remained lower than in other European countries. Nephrotic syndrome was the indication for renal biopsy in over 50% of cases. Glomerulonephritis (GN) was the main histological diagnosis in 91% of cases, of which 56% were primary GN and 35% were secondary GN. The frequency of various types of primary GN was: membranoproliferative GN (MPGN) - 29.3%, membranous nephropathy (MN) -27.5%, focal segmental glomerulosclerosis (FSGS) - 17.2%, mesangial GN (including IgAN) -13.7%, crescentic GN - 9.4%, and minimal change disease (MCD) - 2.5%. Compared to the previously reported period (1994-2004), we observed a significant decrease in the frequency of MPGN and significant increases in the frequency of FSGS and, particularly MN - which more than doubled.

CONCLUSION

We report significant changes in the histological spectrum of GN in North-Eastern Romania in 2005-2010, compared to the previously reported 10-yrs. These changes seem to be following a trend that has also been observed in Western countries a few decades ago, and which may have a socioeconomic explanation.

Non-steroidal anti-inflammatory drugs and chronic kidney disease progression: a systematic review

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely regarded as one risk factor, which influences chronic kidney disease (CKD) progression. However, previous literature reviews have not quantified the risk in moderate to severe CKD patients.

OBJECTIVE

To estimate the strength of association between chronic NSAID use and CKD progression.

METHODS

We conducted a systematic review and meta-analysis of observational general practice or population studies featuring patients aged 45 years and over. The electronic databases searched were MEDLINE, EMBASE, Cochrane, AMED, BNI and CINAHL until September 2011 without date or language restrictions. Searches included the reference lists of relevant identified studies, WEB of KNOWLEDGE, openSIGLE, specific journals, the British Library and expert networks. For relevant studies, random effects meta-analysis was used to estimate the association between NSAID use and accelerated CKD progression (estimated glomerular filtration rate decline ≥ 15 ml/min/1.73 m2).

RESULTS

From a possible 768 articles, after screening and selection, seven studies were identified (5 cohort, 1 case-control and 1 cross-sectional) and three were included in the meta-analysis. Regular-dose NSAID use did not significantly affect the risk of accelerated CKD progression; pooled odds ratio (OR) = 0.96 (95%CI: 0.86-1.07), but high-dose NSAID use significantly increased the risk of accelerated CKD progression; pooled OR = 1.26 (95%CI: 1.06-1.50).

CONCLUSIONS

The avoidance of NSAIDs in the medium term is unnecessary in patients with moderate to severe CKD, if not otherwise contraindicated. As the definition of high-dose of NSAID use remains unclear, the lowest effective dose of NSAIDs should be prescribed where indicated.

Pathogenic and protective role of macrophages in kidney disease

Macrophages (MΦ) are located throughout kidney tissue, where they play important roles in homeostasis, surveillance, tolerance, and cytoprotection. MΦ are highly heterogeneous cells and exhibit distinct phenotypic and functional characteristics depending on their microenvironment and the disease type and stage. Recent studies have identified a dual role for MΦ in several murine models of kidney disease. In this review, we discuss the pathogenic and protective roles of the various MΦ subsets in experimental and human kidney diseases and summarize current progress toward the therapeutic use of MΦ in kidney diseases.

Lifestyle-related factors, obesity, and incident microalbuminuria: the CARDIA (Coronary Artery Risk Development in Young Adults) study

BACKGROUND

Modifiable lifestyle-related factors are associated with risk of coronary heart disease and may also influence kidney disease risk.

STUDY DESIGN

Community-based prospective cohort study.

SETTING & PARTICIPANTS

2,354 African American and white participants aged 28-40 years without baseline microalbuminuria or estimated glomerular filtration rate <60 mL/min/1.73 m² recruited from 4 US centers: Birmingham, AL; Chicago, IL; Minneapolis, MN; and Oakland, CA.

FACTORS

Current smoking, physical activity, fast food habits, obesity, and diet quality, which was based on 8 fundamental components of the Dietary Approaches to Stop Hypertension (DASH) diet, including increased intake of fruits, vegetables, low-fat dairy products, whole grains, and nuts and legumes and reduced intake of sodium, sugar-sweetened beverages, and red and processed meats.

OUTCOMES & MEASUREMENTS

Spot urine albumin-creatinine ratios were obtained at baseline (1995-1996) and three 5-year follow-up examinations (5, 10, and 15 years' follow-up). Incident microalbuminuria was defined as the presence of age- and sex-adjusted albumin-creatinine ratio ≥25 mg/g at 2 or more of the successive follow-up examinations.

RESULTS

During the 15-year follow-up, 77 (3.3%) individuals developed incident microalbuminuria. After multivariable adjustment, poor diet quality (OR, 2.0; 95% CI, 1.1-3.4) and obesity (OR, 1.9; 95% CI, 1.1-3.3) were associated significantly with microalbuminuria; current smoking (OR, 1.6; 95% CI, 0.9-2.8) was associated with microalbuminuria, although the CI crossed 1.0. Neither low physical activity (OR, 1.0; 95% CI, 0.5-1.8) nor fast food consumption (OR, 1.2; 95% CI, 0.7-2.3) was associated with microalbuminuria. Compared with individuals with no unhealthy lifestyle-related factors (poor diet quality, current smoking, and obesity), adjusted odds of incident microalbuminuria were 131%, 273%, and 634% higher for the presence of 1 (OR, 2.3; 95% CI, 1.3-4.3), 2 (OR, 3.7; 95% CI, 1.8-7.7), and 3 (OR, 7.3; 95% CI, 2.1-26.1) unhealthy lifestyle-related factors.

LIMITATIONS

Self-reported dietary history and physical activity, low number of outcomes.

CONCLUSIONS

Consuming an unhealthy diet and obesity are associated with incident microalbuminuria.

Sex, weight status, and chronic kidney disease among African Americans: the Jackson Heart Study

BACKGROUND

Obesity has been shown to have implications for chronic kidney disease (CKD); however, it has received minimal attention from scientists studying CKD among African Americans.

OBJECTIVES

The purpose of this study was to examine the manner in which weight status has implications for CKD among this group through analysis of data drawn from the Jackson Heart Study (JHS).

DESIGN

Cross-sectional analysis of a single-site longitudinal population-based cohort.

PARTICIPANTS

The data for this study were drawn from the baseline examination of the Jackson Heart Study (JHS). The analytic cohort consisted of 3430 African American men and women (21-84 years of age) living in the tricounty area of the Jackson, Mississippi metropolitan areas with complete data to determine CKD status.

MAIN MEASUREMENTS

The primary dependent variable was CKD (defined as the presence of albuminuria or reduced estimated glomerular filtration rate <60 mL/min per 1.73 m(2)). Weight status, the primary predictor, was a 4-category measure based on body mass index.

RESULTS

Associations were explored through bivariable analyses and multivariable logistic regression analyses adjusting for CKD, weight status, diabetes, hypertension, and cardiovascular disease risk factors as well as demographic factors. The prevalence of CKD in the JHS was 20%. The proportion of overweight, class I, and class II obese individuals was 32.5%, 26.9%, and 26.2% respectively. In the pooled model, weight status was not found to be associated with CKD; however, subgroup analysis revealed that class II obesity was associated with CKD among men (odds ratio, 2.37; confidence interval, 1.34-4.19) but not among women (odds ratio, 1.32; confidence interval, 0.88-1.98). The relationship between CKD prevalence and diabetes and CKD prevalence and hypertension varied by sex and differed across weight categories.

CONCLUSIONS

Weight status has implications for CKD among the JHS participants, and this study underscores the need for additional research investigating the relationship between weight status, sex, and CKD among African Americans.

The complement cascade in kidney disease: from sideline to center stage

Activation of the complement pathway is implicated in the pathogenesis of many kidney diseases. The pathologic and clinical features of these diseases are determined in part by the mechanism and location of complement activation within the kidney parenchyma. This review describes the physiology, action, and control of the complement cascade and explains the role of complement overactivation and dysregulation in kidney disease. There have been recent advances in the understanding of the effects of upregulation of the complement cascade after kidney transplantation. Complement plays an important role in initiating and propagating damage to transplanted kidneys in ischemia-reperfusion injury, antibody-mediated rejection, and cell-mediated rejection. Complement-targeting therapies presently are in development, and the first direct complement medication for kidney disease was licensed in 2011. The potential therapeutic targets for anticomplement drugs in kidney disease are described. Clinical and experimental studies are ongoing to identify further roles for complement-targeting therapy.

Applications of metabolomics for kidney disease research: from biomarkers to therapeutic targets

Metabolomics is one of the relative newcomers of the omics techniques and is likely the one most closely related to actual real-time disease pathophysiology. Hence, it has the power to yield not only specific biomarkers but also insight into the pathophysiology of disease. Despite this power, metabolomics as applied to kidney disease is still in its early adolescence and has not yet reached the mature stage of clinical application, i.e., specific biomarker and therapeutic target discovery. On the other hand, the insight gained from hints into what makes these diseases tick, as is evident from the metabolomics pathways which have been found to be altered in kidney cancer, are now beginning to bear fruit in leading to potential therapeutic targets. It is quite likely that, with greater numbers of clinical materials and with more investigators jumping into the field, metabolomics may well change the course of kidney disease research.

Challenges of kidney care in a resource poor nation: A study of private kidney care centre in Nigeria

BACKGROUND

Resource poor nations are froth with various confounding challenges in their social, political, financial, physical and healthcare needs. Care of patients with health problems', including those with kidney related disorders is associated with many challenges. This study is aimed to highlight the challenges of kidney care in a resource poor nation.

MATERIALS AND METHODS

The activity of a private kidney care centre in Nigeria was reviewed from establishment to 6 months of operation. The details were documented and analysed.

RESULT

The commencement of the kidney care centre was delayed as a result of financial and bureaucratic challenges. A total of 64 patients were seen during the period studied, 59.4% were male and the mean age was 48.2±5.5 years. 40.3% of the patients had chronic kidney disease. Twenty patients had haemodialysis however only 2 patients sustained the dialysis for the period studied. Most patients were unable to adhere to medication. The centre still depend on the parent hospital financially.

CONCLUSION

The challenges of kidney care in resource poor nation are numerous and multifactorial.

Survival and distribution of injected haematopoietic stem cells in acute kidney injury

BACKGROUND

Endogenous bone marrow-derived cells are known to incorporate into renal epithelium at a low rate. Haematopoietic stem cells (HSCs) rather than mesenchymal stem cells (MSC) are responsible for this phenomenon. MSCs have the potential to ameliorate kidney function after acute kidney injury (AKI) without directly repopulating the tubules. However, little is known about the short-term effect of HSCs.

METHODS

In this article, we analysed the survival rate and organ distribution of isolated rat HSCs injected into the renal artery after ischaemic renal injury, using quantitative real-time PCR, as well as their impact on renal function and histomorphology.

RESULTS

Intra-arterially injected Lin(-)CD90(+) HSCs were detected in the kidney at significant amounts only within the first 24 h after injection and were virtually absent by Day 2. Compared with control animals, no differences were seen after HSC administration with respect to kidney function or histomorphologic changes of AKI. At Day 7 HSCs were again readily detectable in the kidney suggesting a redistribution of cells at later time points. Of note, HSCs did not seem to have an exclusive tropism for the injured kidney but were detectable in the lungs, liver, spleen, heart and brain at all time points.

CONCLUSIONS

Injected HSCs do not appear to significantly contribute to tubular repair or ameliorate renal damage in ischaemic AKI although they may show considerable engraftment in various organs. These data further challenge the concept that injection of HSCs may be used as a therapeutic approach in treating AKI.