Renoprotective benefits of RAS inhibition: from ACEI to angiotensin II antagonists

Functional MRI evaluation of blood oxygen dependent (BOLD) in renal allograft dysfunction: a prospective study

BACKGROUND

Blood oxygen level dependent-magnetic resonance imaging (BOLD-MRI) is a non-invasive functional imaging technique that can be used to assess renal allograft dysfunction.

PURPOSE

To evaluate the diagnostic performance of BOLD-MRI using a 3-T scanner in discriminating causes of renal allograft dysfunction in the post-transplant period.

MATERIAL AND METHODS

This prospective study was conducted on 112 live donor-renal allograft recipients: 53 with normal graft function, as controls; 18 with biopsy-proven acute rejection (AR); and 41 with biopsy-proven acute tubular necrosis (ATN). Multiple fast-field echo sequences were performed to obtain T2*-weighted images. Cortical R2* (CR2*) level, medullary R2* (MR2*) level, and medullary over cortical R2* ratio (MCR) were measured in all participants.

RESULTS

The mean MR2* level was significantly lower in the AR group (20.8 ± 2.8/s) compared to the normal group (24 ± 2.4/s, P <0.001) and ATN group (27.4 ± 1.7/s, P <0.001). The MCR was higher in ATN group (1.47 ± 0.18) compared to the AR group (1.18 ± 0.17) and normal functioning group (1.34 ± 0.2). Both MR2* (area under the curve [AUC] = 0.837, P <0.001) and MCR (AUC = 0.727, P = 0.003) can accurately discriminate ATN from AR, however CR2* (AUC = 0.590, P = 0.237) showed no significant difference between both groups.

CONCLUSION

In early post-transplant renal dysfunction, BOLD-MRI is a valuable non-invasive diagnostic technique that can differentiate between AR and ATN by measuring changes in intra-renal tissue oxygenation.

Dihydropyridine Calcium Channel Blockers and Kidney Outcomes

BACKGROUND

Early trials of dihydropyridine calcium channel blockers (DCCBs) suggest a detrimental effect on intraglomerular pressure and an association with albuminuria.

OBJECTIVE

We sought to evaluate the associations of DCCB initiation with albuminuria and kidney failure with replacement therapy (KFRT) and to determine whether renin-angiotensin system (RAS) blockade modified these associations.

DESIGN

We conducted a target trial emulation study using a new user, active comparator design and electronic health record data from Geisinger Health.

PARTICIPANTS

We included patients without severe albuminuria or KFRT who were initiated on a DCCB or thiazide (active comparator) between January 1, 2004, and December 31, 2019.

MAIN MEASURES

Using inverse probability of treatment weighting, we performed doubly robust Cox proportional hazards regression to estimate the association of DCCB initiation with incident severe albuminuria (urine albumin to creatinine ratio > 300 mg/g) and KFRT, overall and stratified by RAS blocker use.

KEY RESULTS

There were 11,747 and 26,758 eligible patients initiating a DCCB and thiazide, respectively, with a weighted baseline mean age of 60 years, systolic blood pressure of 143 mm Hg, and eGFR of 86 mL/min/1.73 m2, and with a mean follow-up of 8 years. Compared with thiazides, DCCBs were significantly associated with the development of severe albuminuria (hazard ratio [HR], 1.29; 95% confidence interval [CI], 1.16-1.43), with attenuation of risk in the presence of RAS blockade (P for interaction < 0.001). The risk of KFRT was increased among patients without RAS blockade (HR, 1.66; 95% CI, 1.19-2.31), but not with RAS blockade (P for interaction = 0.005).

CONCLUSIONS

DCCBs were associated with increased risk of albuminuria and, in the absence of RAS blockade, KFRT. These findings suggest coupling DCCB therapy with RAS blockade may mitigate adverse kidney outcomes.

Zinc deficiency induces hypertension by paradoxically amplifying salt sensitivity under high salt intake in mice

BACKGROUND

Hypertension is one of the major etiologies that cause chronic kidney disease (CKD) and can exacerbate kidney dysfunction. Zinc is an essential trace element playing a role in blood pressure regulation, and zinc deficiency, a common comorbidity in patients with CKD, can cause hypertension. However, the precise mechanism underlying zinc deficiency-induced hypertension is unknown. Sodium (Na+) retention due to inappropriate Na+ reabsorption in the renal tubule is the principal pathophysiology of hypertension. Therefore, this study aimed to investigate the association between zinc deficiency and salt sensitivity.

METHODS

Adult mice were fed a zinc-adequate (ZnA) or zinc-deficient (ZnD) diet combined with/without high salt in drinking water (HS) for 4 weeks (n = 6 each). Changes in blood pressure, urinary sodium excretion, and the expressions of the proximal tubular Na+ transporter, Na+/H+ exchanger 3 (NHE3), which mostly contributes to filtered Na+ reabsorption and the downstream Na+-Cl- transporter (NCC) were analyzed.

RESULTS

Urinary Na+ excretion significantly increased in ZnD mice, indicating that zinc deficiency causes natriuresis. NHE3 expressions were significantly suppressed, whereas NCC was upregulated in ZnD mice. Interestingly, the combination of high salt and ZnD diet (HS-ZnD) reversed the urinary Na+ loss. The NCC remained activated and NHE3 expressions paradoxically increased in HS-ZnD mice compared with those fed the combination of high salt and ZnA diet. In addition, blood pressure significantly increased only in HS-ZnD mice.

CONCLUSION

The combination of zinc deficiency and high salt causes hypertension. Zinc is associated with salt-sensitivity, potentially through NHE3 and NCC regulation.

Network pharmacology combined with Mendelian randomization analysis to identify the key targets of renin-angiotensin-aldosterone system inhibitors in the treatment of diabetic nephropathy

Background

Diabetic Nephropathy (DN) is one of the microvascular complications of diabetes. The potential targets of renin-angiotensin-aldosterone system (RAAS) inhibitors for the treatment of DN need to be explored.

Methods

The GSE96804 and GSE1009 datasets, 729 RAAS inhibitors-related targets and 6,039 DN-related genes were derived from the public database and overlapped with the differentially expressed genes (DN vs. normal) in GSE96804 to obtain the candidate targets. Next, key targets were screened via the Mendelian randomization analysis and expression analysis. The diagnostic nomogram was constructed and assessed in GSE96804. Additionally, enrichment analysis was conducted and a 'core active ingredient-key target-disease pathway' network was established. Finally, molecular docking was performed.

Results

In total, 60 candidate targets were derived, in which CTSC and PDE5A were screened as the key targets and had a causal association with DN as the protective factors (P < 0.05, OR < 1). Further, a nomogram exhibited pretty prediction efficiency. It is indicated that Benadryl hydrochloride might play a role in the DN by affecting the pathways of 'cytokine cytokine receptor interaction', etc. targeting the CTSC. Moreover, PDE5A might be involved in 'ECM receptor interaction', etc. for the effect of NSAID, captopril, chlordiazepoxide on DN. Molecular docking analysis showed a good binding ability of benadryl hydrochloride and CTSC, NSAID and PDE5A. PTGS2, ITGA4, and ANPEP are causally associated with acute kidney injury.

Conclusion

CTSC and PDE5A were identified as key targets for RAAS inhibitors in the treatment of DN, which might provide some clinical significance in helping to diagnose and treat DN. Among the targets of RAAS inhibitors, PTGS2, ITGA4 and ANPEP have a causal relationship with acute kidney injury, which is worthy of further clinical research.

Elevated urine albumin creatinine ratio increases cardiovascular mortality in coronary artery disease patients with or without type 2 diabetes mellitus: a multicenter retrospective study

BACKGROUND

Albuminuria has been suggested as an atherosclerotic risk factor among the general population. However, whether this association will be amplified in patients with coronary artery disease (CAD) is unknown. It is also unknown whether diabetes mellitus confounds the association. We aim to analyse the prognosis of elevated urine albumin creatinine ratio (uACR) in the CAD population with or without type 2 diabetes mellitus (T2DM).

METHODS

This multi-center registry cohort study included 5,960 patients with CAD. Patients were divided into T2DM and non-T2DM group, and baseline uACR levels were assessed on three grades (low: uACR < 10 mg/g, middle: 10 mg/g ≤ uACR < 30 mg/g, and high: uACR ≥ 30 mg/g). The study endpoints were cardiovascular mortality and all-cause mortality.

RESULTS

During the median follow-up of 2.2 [1.2-3.1] years, 310 (5.2%) patients died, of which 236 (4.0%) patients died of cardiovascular disease. CAD patients with elevated uACR had a higher risk of cardiovascular mortality (middle: HR, 2.32; high: HR, 3.22) than those with low uACR, as well as all-cause mortality. Elevated uACR increased nearly 1.5-fold risk of cardiovascular mortality (middle: HR, 2.33; high: HR, 2.34) among patients without T2DM, and increased 1.5- fold to 3- fold risk of cardiovascular mortality in T2DM patients (middle: HR, 2.49; high: HR, 3.98).

CONCLUSIONS

Even mildly increased uACR could increase the risk of cardiovascular mortality in patients with CAD, especially when combined with T2DM.

Blockade of the mineralocorticoid receptor improves markers of human endothelial cell dysfunction and hematological indices in a mouse model of sickle cell disease

Increased endothelin-1 (ET-1) levels in patients with sickle cell disease (SCD) and transgenic mouse models of SCD contribute to disordered hematological, vascular, and inflammatory responses. Mineralocorticoid receptor (MR) activation by aldosterone, a critical component of the Renin-Angiotensin-Aldosterone-System, modulates inflammation and vascular reactivity, partly through increased ET-1 expression. However, the role of MR in SCD remains unclear. We hypothesized that MR blockade in transgenic SCD mice would reduce ET-1 levels, improve hematological parameters, and reduce inflammation. Berkeley SCD (BERK) mice, a model of severe SCD, were randomized to either sickle standard chow or chow containing the MR antagonist (MRA), eplerenone (156 mg/Kg), for 14 days. We found that MRA treatment reduced ET-1 plasma levels (p = .04), improved red cell density gradient profile (D₅₀ ; p < .002), and increased mean corpuscular volume in both erythrocytes (p < .02) and reticulocytes (p < .024). MRA treatment also reduced the activity of the erythroid intermediate-conductance Ca²⁺ -activated K⁺ channel - K_Ca 3.1 (Gardos channel, KCNN4), reduced cardiac levels of mRNAs encoding ET-1, Tumor Necrosis Factor Receptor-1, and protein disulfide isomerase (PDI) (p < .01), and decreased plasma PDI and myeloperoxidase activity. Aldosterone (10^-8  M for 24 h in vitro) also increased PDI mRNA levels (p < .01) and activity (p < .003) in EA.hy926 human endothelial cells, in a manner blocked by pre-incubation with the MRA canrenoic acid (1 μM; p < .001). Our results suggest a novel role for MR activation in SCD that may exacerbate SCD pathophysiology and clinical complications.

Kidney disease in adults with Prader-Willi syndrome: international cohort study and systematic literature review

Background

Prader-Willi syndrome (PWS) is a rare, complex, genetic disorder characterized by hyperphagia, hypotonia, delayed psychomotor development, low muscle mass and hypothalamic dysfunction. Adults with PWS often have obesity, hypertension and type 2 diabetes mellitus (DM2), known risk factors for cardiovascular disease (CVD) and chronic kidney disease (CKD). Early symptoms of CVD and CKD may be masked by intellectual disability and inability to express physical complaints. Furthermore, kidney diseases are often asymptomatic. Therefore, renal and cardiovascular disease might be missed in patients with PWS. Microalbuminuria is an early sign of microvascular damage in the kidneys and other vascular beds. Therefore, we screened our adult PWS cohort for the presence of elevated urinary albumin and (micro)albuminuria.

Methods

We retrospectively collected anthropometric measurements, blood pressure, medical history, medication use, urine dipstick and biochemical measurements form electronic patient files. In addition, we performed a systematic literature review on kidney disease in PWS.

Results

We included 162 adults with genetically confirmed PWS (56% male, median age 28 years), of whom 44 (27%) had DM2. None had known CVD. All subjects had normal estimated glomerular filtration rate (eGFR) according to non-PWS reference intervals. Elevated urinary albumin or (micro)albuminuria was present in 28 (18%); 19 out of 75 (25%) had an increased urinary albumin-to-creatinine ratio (UACR) and 10 out of 57 (18%) had an increased urinary protein-to-creatinine ratio. Elevated urinary albumin was present at a young age (median age 26 (IQR 24-32) years) and was associated with an significantly higher BMI and LDL-cholesterol levels and higher prevalence of DM2, hypertension and dyslipidemia than those with normal UACR (p=0.027, p=0.019, p<0.001, p<0.001, p=0.011 and respectively).

Conclusion

Upon screening, one in every five adults with PWS had increased urinary albumin or (micro)albuminuria, early signs of microvascular disease. All had normal eGFR, according to non-PWS reference intervals, and none had a formal diagnosis of CVD. As muscle mass is low in PWS, creatinine levels and eGFR may be spuriously normal. Urinalysis in this patient group can be used as a screening tool for microvascular (kidney) disease. We propose an algorithm for the detection and management of microvascular disease in adults with PWS.

Translation Animal Models of Diabetic Kidney Disease: Biochemical and Histological Phenotypes, Advantages and Limitations

Animal models play a crucial role in studying the pathogenesis of diseases, developing new drugs, identifying disease risk markers, and improving means of prevention and treatment. However, modeling diabetic kidney disease (DKD) has posed a challenge for scientists. Although numerous models have been successfully developed, none of them can encompass all the key characteristics of human DKD. It is essential to choose the appropriate model according to the research needs, as different models develop different phenotypes and have their limitations. This paper provides a comprehensive overview of biochemical and histological phenotypes, modeling mechanisms, advantages and limitations of DKD animal models, in order to update relevant model information and provide insights and references for generating or selecting the appropriate animal models to fit different experimental needs.

Dapagliflozin ameliorates diabetic renal injury through suppressing the self-perpetuating cycle of inflammation mediated by HMGB1 feedback signaling in the kidney

Dapagliflozin, the Sodium-glucose cotransporter 2 (SGLT2) inhibitor class of glucose-lowering agents, has shown the significantly nephroprotective effects to reduce the risk of kidney failure in diabetes. However, the underlying mechanisms are incompletely understood to explain the beneficial effects of dapagliflozin on kidney function. Here, we demonstrated that the administered of dapagliflozin for 12 weeks improved the proteinuria, histomorphology damage, oxidative stress, and macrophage infiltrations in the kidney of streptozotocin (STZ)-induced diabetic mice. Meanwhile, dapagliflozin attenuated the renal inflammation and fibrosis by reducing the pro-inflammatory factors interleukin-6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α) and anti-fiber factor fibronectin (FN) and elevating the anti-inflammatory factor IL-10. Our data revealed that dapagliflozin exerted anti-inflammatory effects by inhibiting the activation of high mobility group box 1 (HMGB1)/TLR2/4/NF-κB signaling pathway. Consistently, we found that dapagliflozin suppressed the expression of HMGB1 and downstream TLR2/4/NF-κB signaling proteins in the human proximal tubular (HK-2) stimulated by high glucose and lipids or HMGB1 and RAW264.7 cells stimulated by IL-1β, respectively. Further experiments were performed in the indirect co-culture model of RAW264.7 and HK-2 cells induced by high glucose and lipids. The results again confirmed the effects of dapagliflozin on alleviating inflammatory response and regulating the proportions of M1/M2 macrophage. It is indicated that the feedback signaling of HMGB1 between the tubules and macrophage involves in the persistence of the inflammation. These data demonstrate that dapagliflozin suppress the self-perpetuating inflammation by blocking the feedback loop of HMGB1 in the kidney, which contribute to ameliorate the renal injury in diabetes.

Novel insights in classic versus relative glomerular hyperfiltration and implications on pharmacotherapy

PURPOSE OF REVIEW

Glomerular filtration rate (GFR) assessment and its estimation (eGFR) is a long-lasting challenge in medicine and public health. Current eGFR formulae are indexed for standardized body surface area (BSA) of 1.73 m2, ignoring persons and populations wherein the ratio of BSA or metabolic rate to nephron number might be different, due to increased BSA, increased metabolic rate or reduced nephron number. These equations are based on creatinine, cystatin C or a combination of the two, which adds another confounder to eGFR assessment. Unusually high GFR values, also known as renal hyperfiltration, have not been well defined under these equations.

RECENT FINDINGS

Special conditions such as solitary kidney in kidney donors, high dietary protein intake, obesity and diabetes are often associated with renal hyperfiltration and amenable to errors in GFR estimation. In all hyperfiltration types, there is an increased intraglomerular pressure that can be physiologic, but its persistence over time is detrimental to glomerulus leading to progressive glomerular damage and renal fibrosis. Hyperfiltration might be underdiagnosed due to BSA standardization embedded in the formula. Hence, timely intervention is delayed. Reducing intraglomerular pressure in diabetes can be achieved by SGLT2 inhibitors or low protein diet to reverse the glomerulopathy process.

SUMMARY

Accurate identification of glomerular hyperfiltration as a pre-CKD condition needs accurate estimation of GFR in the above normal range should establish a threshold for timely intervention.

Urinary Exosomal MicroRNAs as Biomarkers for Obesity-Associated Chronic Kidney Disease

The early detection of chronic kidney disease (CKD) is key to reducing the burden of disease and rising costs of care. This need has spurred interest in finding new biomarkers for CKD. Ideal bi-omarkers for CKD should be: easy to measure; stable; reliably detected, even when interfering substances are present; site-specific based on the type of injury (tubules vs. glomeruli); and its changes in concentration should correlate with disease risk or outcome. Currently, no single can-didate biomarker fulfills these criteria effectively, and the mechanisms underlying kidney fibrosis are not fully understood; however, there is growing evidence in support of microRNA-mediated pro-cesses. Specifically, urinary exosomal microRNAs may serve as biomarkers for kidney fibrosis. In-creasing incidences of obesity and the recognition of obesity-associated CKD have increased interest in the interplay of obesity and CKD. In this review, we provide: (1) an overview of the current scope of CKD biomarkers within obese individuals to elucidate the genetic pathways unique to obesi-ty-related CKD; (2) a review of microRNA expression in obese individuals with kidney fibrosis in the presence of comorbidities, such as diabetes mellitus and hypertension; (3) a review of thera-peutic processes, such as diet and exercise, that may influence miR-expression in obesity-associated CKD; (4) a review of the technical aspects of urinary exosome isolation; and (5) future areas of research.

Gain-of-function, focal segmental glomerulosclerosis Trpc6 mutation minimally affects susceptibility to renal injury in several mouse models

Mutations in TRPC6 are a cause of autosomal dominant focal segmental glomerulosclerosis in humans. Many of these mutations are known to have a gain-of-function effect on the non-specific cation channel function of TRPC6. In vitro studies have suggested these mutations affect several signaling pathways, but in vivo studies have largely compared wild-type and Trpc6-deficient rodents. We developed mice carrying a gain-of-function Trpc6 mutation encoding an E896K amino acid change, corresponding to a known FSGS mutation in TRPC6. Homozygous mutant Trpc6 animals have no appreciable renal pathology, and do not develop albuminuria until very advanced age. The Trpc6E896K mutation does not impart susceptibility to PAN nephrosis. The animals show a slight delay in recovery from the albumin overload model. In response to chronic angiotensin II infusion, Trpc6E896K/E896K mice have slightly greater albuminuria initially compared to wild-type animals, an effect that is lost at later time points, and a statistically non-significant trend toward more glomerular injury. This phenotype is nearly opposite to that of Trpc6-deficient animals previously described. The Trpc6 mutation does not appreciably impact renal interstitial fibrosis in response to either angiotensin II infusion, or folate-induced kidney injury. TRPC6 protein and TRPC6-agonist induced calcium influx could not be detected in glomeruli. In sum, these findings suggest that a gain-of-function Trpc6 mutation confers only a mild susceptibility to glomerular injury in the mouse.

Educational Review: The Impact of Perinatal Oxidative Stress on the Developing Kidney

Oxidative stress occurs when there is an imbalance between reactive oxygen species/reactive nitrogen species and antioxidant systems. The interplay between these complex processes is crucial for normal pregnancy and fetal development; however, when oxidative stress predominates, pregnancy related complications and adverse fetal programming such as preterm birth ensues. Understanding how oxidative stress negatively impacts outcomes for the maternal-fetal dyad has allowed for the exploration of antioxidant therapies to prevent and/or mitigate disease progression. In the developing kidney, the negative impact of oxidative stress has also been noted as it relates to the development of hypertension and kidney injury mostly in animal models. Clinical research addressing the implications of oxidative stress in the developing kidney is less developed than that of the neurodevelopmental and respiratory conditions of preterm infants and other vulnerable neonatal groups. Efforts to study the oxidative stress pathway along the continuum of the perinatal period using a team science approach can help to understand the multi-organ dysfunction that the maternal-fetal dyad sustains and guide the investigation of antioxidant therapies to ameliorate the global toxicity. This educational review will provide a comprehensive and multidisciplinary perspective on the impact of oxidative stress during the perinatal period in the development of maternal and fetal/neonatal complications, and implications on developmental programming of accelerated aging and cardiovascular and renal disease for a lifetime.

Angiotensin receptor-neprilysin inhibitors: Comprehensive review and implications in hypertension treatment

Angiotensin receptor-neprilysin inhibitors (ARNIs) are a new class of cardiovascular agents characterized by their dual action on the major regulators of the cardiovascular system, including the renin-angiotensin system (RAS) and the natriuretic peptide (NP) system. The apparent clinical benefit of one ARNI, sacubitril/valsartan, as shown in clinical trials, has positioned the drug class as a first-line therapy in patients with heart failure, particularly with reduced ejection fraction. Accumulating evidence also suggests that sacubitril/valsartan is superior to conventional RAS blockers in lowering blood pressure in patients with hypertension. To decide whether to apply an ARNI to treat hypertension clinically, it is important to understand the potential properties of the drug in modulating multiple factors inside and outside the cardiovascular system beyond its effect on reducing peripheral blood pressure. In this context, ARNIs are distinct from preexisting antihypertensive medications in terms of the multiple actions of NPs in various organs and the pharmacological potential of neprilysin inhibitors to modulate multiple cardiac and noncardiac peptides. In particular, analysis of the clinical trials of sacubitril/valsartan implies that ARNIs can provide additional clinical benefits independent of their original purpose, including alleviation of glycemic control and renal impairment in patients with heart failure. Understanding the potential mechanisms of action of ARNIs will help interpret the relevance of their additional benefits beyond lowering blood pressure in hypertension. This review summarizes the comprehensive clinical evidence and relevance of ARNIs by specifically focusing on the potential properties of this new drug class in treating patients with hypertension.

Medicaid Expansion and Incidence of Kidney Failure among Nonelderly Adults

BACKGROUND

Low-income individuals without health insurance have limited access to health care. Medicaid expansions may reduce kidney failure incidence by improving access to chronic disease care.

METHODS

Using a difference-in-differences analysis, we examined the association between Medicaid expansion status under the Affordable Care Act (ACA) and the kidney failure incidence rate among all nonelderly adults, aged 19-64 years, in the United States, from 2012 through 2018. We compared changes in kidney failure incidence in states that implemented Medicaid expansions with concurrent changes in nonexpansion states during pre-expansion, early postexpansion (years 2 and 3 postexpansion), and later postexpansion (years 4 and 5 postexpansion).

RESULTS

The unadjusted kidney failure incidence rate increased in the early years of the study period in both expansion and nonexpansion states before stabilizing. After adjustment for population sociodemographic characteristics, Medicaid expansion status was associated with 2.20 fewer incident cases of kidney failure per million adults per quarter in the early postexpansion period (95% CI, -3.89 to -0.51) compared with nonexpansion status, a 3.07% relative reduction (95% CI, -5.43% to -0.72%). In the later postexpansion period, Medicaid expansion status was not associated with a statistically significant change in kidney failure incidence (-0.56 cases per million per quarter; 95% CI, -2.71 to 1.58) compared with nonexpansion status and the pre-expansion time period.

CONCLUSIONS

The ACA Medicaid expansion was associated with an initial reduction in kidney failure incidence among the entire, nonelderly, adult population in the United States; but the changes did not persist in the later postexpansion period. Further study is needed to determine the long-term association between Medicaid expansion and changes in kidney failure incidence.

Association of Blood Pressure Genetic Risk Score with Cardiovascular Disease and CKD Progression: Findings from the CRIC Study

Background

In the general population, genetic risk for high BP has been associated with cardiovascular disease, but not kidney function or incident CKD. These relationships have not been studied longitudinally in participants with CKD. We examined whether BP genetic risk predicts cardiovascular disease and kidney disease progression in patients with CKD.

Methods

We included 1493 African- and 1581 European-ancestry participants from the Chronic Renal Insufficiency Cohort who were followed for 12 years. We examined associations of BP genetic risk scores with development of cardiovascular disease (myocardial infarction, congestive heart failure, or stroke) and CKD progression (incident ESKD or halving of eGFR) using Cox proportional hazards models. Analyses were stratified by race and included adjustment for age, sex, study site, and ancestry principal components.

Results

Among European-ancestry participants, each SD increase in systolic BP and pulse pressure genetic risk score conferred a 15% (95% CI, 4% to 27%) and 11% (95% CI, 1% to 23%), respectively, higher risk of cardiovascular disease, with a similar, marginally significant trend for diastolic BP. Among African-ancestry participants, each SD increase in systolic and diastolic BP genetic risk score conferred a 10% (95% CI, 1% to 20%) and 9% (95% CI, 0% to 18%), respectively, higher risk of cardiovascular disease. Higher genetic risk was not associated with CKD progression.

Conclusions

Genetic risk for elevation in BP was associated with increased risk of cardiovascular disease, but not CKD progression.

Towards Better Drug Repositioning: Targeted Immunoinflammatory Therapy for Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common and important microvascular complications of diabetes mellitus (DM). The main clinical features of DN are proteinuria and a progressive decline in renal function, which are associated with structural and functional changes in the kidney. The pathogenesis of DN is multifactorial, including genetic, metabolic, and haemodynamic factors, which can trigger a sequence of events. Controlling metabolic risks such as hyperglycaemia, hypertension, and dyslipidaemia is not enough to slow the progression of DN. Recent studies emphasized immunoinflammation as a critical pathogenic factor in the progression of DN. Therefore, targeting inflammation is considered a potential and novel treatment strategy for DN. In this review, we will briefly introduce the inflammatory process of DN and discuss the anti-inflammatory effects of antidiabetic drugs when treating DN.

Effects of inhibition of the renin-angiotensin system on hypertension-induced target organ damage: clinical and experimental evidence

The dysregulation of renin-angiotensin-system (RAS) plays a pivotal role in hypertension and in the development of the related target organ damage (TOD). The main goal of treating hypertension is represented by the long-term reduction of cardiovascular (CV) risk. RAS inhibition either by angiotensin converting enzyme (ACE)-inhibitors or by type 1 Angiotensin II receptors blockers (ARBs), reduce the incidence of CV events in hypertensive patients. Actually, ACE-inhibitors and ARBs have been demonstrated to be effective to prevent, or delay TOD like left ventricular hypertrophy, chronic kidney disease, and atherosclerosis. The beneficial effects of RAS blockers on clinical outcome of hypertensive patients are due to the key role of angiotensin II in the pathogenesis of TOD. In particular, Angiotensin II through an inflammatory-mediated mechanism plays a role in the initiation, progression and vulnerability of atherosclerotic plaque. In addition, Angiotensin II can be considered the hormonal transductor of the pressure overload in cardiac myocytes, and through an autocrine-paracrine mechanism plays a role in the development of left ventricular hypertrophy. Angiotensin II by modulating the redox status and the immune system participates to the development of chronic kidney disease. The RAS blocker should be considered the first therapeutic option in patients with hypertension, even if ACE-inhibitors and ARBs have different impact on CV prevention. ARBs seem to have greater neuro-protective effects, while ACE-inhibitors have greater cardio-protective action.

Beneficial effect of ACE inhibitors on kidney function in polycythemia vera

BACKGROUND

Reduced kidney function has been associated with worse clinical outcomes in patients with myeloproliferative neoplasms (MPN). Statins and angiotensin-converting enzyme inhibitors (ACE-i) have renoprotective properties and their pleiotropic effects might also affect the malignant MPN clone; however, whether concomitant use of statins and ACE‑i has a positive effect on estimated glomerular filtration rate (eGFR) in polycythemia vera (PV) patients is currently unknown.

METHODS

This multicenter retrospective study investigated effects of statins and ACE‑i on 12-month eGFR dynamics in 75 PV patients.

RESULTS

Of the patients 25 (33.3%) had a 10% or more increase in eGFR at 12 months. Univariately, statins (55.5% vs. 16.3%; p = 0.022), ACE‑i (61% vs. 24.6%; p = 0.004), male sex (54.3%, vs. 15%; p < 0.001) and the absence of chronic kidney disease (CKD, 45.5% vs. 16.1%; p = 0.008) were statistically significantly associated with an improvement in eGFR. ACE‑i (p = 0.008), CKD (p < 0.001), male sex (p = 0.004) and higher baseline eGFR (p = 0.007) remained statistically significantly associated with an improvement in eGFR in the multivariate logistic regression model also including statins, hydroxyurea, high-risk disease, cardiovascular risk factors, chronic heart failure and baseline hematocrit.

CONCLUSION

The ACE‑i might have renoprotective properties in PV. Further studies are needed to elucidate whether the use of these drugs could also affect other MPN-related outcomes.

Renin-angiotensin system blockers and 1-year mortality in patients with post-operative acute kidney injury

BACKGROUND

Angiotensin-converting enzyme inhibitor (ACE-I) and angiotensin-receptor blocker (ARB) users may be associated with increased mortality in patients with post-operative acute kidney injury (AKI), but data are limited. We studied whether users of ACE-I/ARBs with AKI after colorectal cancer surgery (CRC) were associated with increased 1-year mortality after AKI.

METHODS

This population-based cohort study in Northern Denmark included patients with AKI within 7 days after CRC surgery during 2005-2014. From reimbursed prescriptions, patients were classified as ACE-I/ARB current, former, or non-users. We computed the cumulative 30-day and 1-year mortality after AKI with 95% confidence intervals (95% CI) using the Kaplan-Meier method (1-survival function). Hazard ratios (HRs) comparing mortality in current and former users with non-users were computed by Cox proportional hazards regression analyses, controlling for potential confounders.

RESULTS

We identified 10 713 CRC surgery patients. A total of 2000 patients had AKI and were included. Thirty-day mortality was 16.5% (95% CI 13.7-19.8), 16.2% (95% CI 11.3-22.8), and 13.4% (95% CI 11.6-15.4) for current, former, and non-users. Adjusted HR was 1.26 (95% CI 0.96-1.65) and 1.19 (95% CI 0.78-1.82) for current and former users compared with non-users. One-year mortality rates were 26.4% (95% CI 22.9-30.4), 29.8% (95% CI 23.2-37.8), and 24.7% (95% CI 22.4-27.2) in current, former, and non-users. Compared with non-users, the adjusted 1-year HR for death in current and former users were 1.29 (95% CI 0.96-1.73) and 1.11 (95% CI 0.91-1.35).

CONCLUSION

Based on our findings, current users of ACE-I/ARB may possibly have a small increase in mortality rate in the year after post-operative AKI, although the degree of certainty is low.

MicroRNAs in Chronic Kidney Disease: Four Candidates for Clinical Application

There are still major challenges regarding the early diagnosis and treatment of chronic kidney disease (CKD), which is in part due to the fact that its pathophysiology is very complex and not clarified in detail. The diagnosis of CKD commonly is made after kidney damage has occurred. This highlights the need for better mechanistic insight into CKD as well as improved clinical tools for both diagnosis and treatment. In the last decade, many studies have focused on microRNAs (miRs) as novel diagnostic tools or clinical targets. MiRs are small non-coding RNA molecules that are involved in post-transcriptional gene regulation and many have been studied in CKD. A wide array of pre-clinical and clinical studies have highlighted the potential role for miRs in the pathogenesis of hypertensive nephropathy, diabetic nephropathy, glomerulonephritis, kidney tubulointerstitial fibrosis, and some of the associated cardiovascular complications. In this review, we will provide an overview of the miRs studied in CKD, especially highlighting miR-103a-3p, miR-192-5p, the miR-29 family and miR-21-5p as these have the greatest potential to result in novel therapeutic and diagnostic strategies.

Understanding the dual mechanism of bioactive peptides targeting the enzymes involved in Renin Angiotensin System (RAS): An in-silico approach

Understanding the dual inhibition mechanism of food derivative peptides targeting the enzymes (Renin and Angiotensin Converting enzyme) in the Renin Angiotensin System. Two peptides RALP and WYT were reported to possess antihypertensive activity targeting both renin and ACE, and we have used molecular docking and molecular dynamics simulation, in order to understand the underlying mechanism. The selected peptides (RALP and WYT) from the series of peptides reported were docked to renin and ACE and two binding modes were selected based on the binding energy, interaction pattern and clusters of docking simulation. The enzyme-peptide complexes for renin and ACE (Renin/RALP_1,2; ACE/RALP_1,2; Renin/WYT_1,2 and ACE/WYT_1,2) were subjected to molecular dynamics simulation. Our results identified that the peptides inhibiting renin, tends to move out of the binding pockets (S1' S2') which is critical for potent binding and occupies the less important pockets (S4 and S3). This could possibly be the reason for its low potency. Whereas, the same peptides targeting ACE, tends to be intact in the pocket because of the metal ion coordination and there is an ample room to improve on its efficacy. Our results further pave way for the biochemist, medicinal chemist to design dual peptides targeting the RAS effectively. Communicated by Ramaswamy H. Sarma.

Renin-angiotensin system blocker use and the risk of acute kidney injury after colorectal cancer surgery: a population-based cohort study

OBJECTIVES

It is unknown whether preoperative use of ACE inhibitors (ACE-I) or angiotensin receptor blockers (ARBs) affects the risk of acute kidney injury (AKI) after colorectal cancer (CRC) surgery. We assessed the impact of preoperative ACE-I/ARB use on risk of AKI after CRC surgery.

DESIGN

Observational cohort study. Patients were divided into three exposure groups-current, former and non-users-through reimbursed prescriptions within 365 days before the surgery. AKI within 7 days after surgery was defined according to the current Kidney Disease Improving Global Outcome consensus criteria.

SETTING

Population-based Danish medical databases.

PARTICIPANTS

A total of 9932 patients undergoing incident CRC surgery during 2005-2014 in northern Denmark were included through the Danish Colorectal Cancer Group Database.

OUTCOME MEASURE

We computed cumulative incidence proportions (risk) of AKI with 95% CIs for current, former and non-users of ACE-I/ARB, including death as a competing risk. We compared current and former users with non-users by computing adjusted risk ratios (aRRs) using log-binomial regression adjusted for demographics, comorbidities and CRC-related characteristics. We stratified the analyses of ACE-I/ARB users to address any difference in impact within relevant subgroups.

RESULTS

Twenty-one per cent were ACE-I/ARB current users, 6.4% former users and 72.3% non-users. The 7-day postoperative AKI risk for current, former and non-users was 26.4% (95% CI 24.6% to 28.3%), 25.2% (21.9% to 28.6%) and 17.8% (17.0% to 18.7%), respectively. The aRRs of AKI were 1.20 (1.09 to 1.32) and 1.16 (1.01 to 1.34) for current and former users, compared with non-users. The relative risk of AKI in current compared with non-users was consistent in all subgroups, except for higher aRR in patients with a history of hypertension.

CONCLUSIONS

Being a current or former user of ACE-I/ARBs is associated with an increased risk of postoperative AKI compared with non-users. Although it may not be a drug effect, users of ACE-I/ARBs should be considered a risk group for postoperative AKI.

Should ACE inhibitors and ARBs be used in combination in children?

The renin-angiotensin-aldosterone system (RAAS) plays a pivotal role in a host of renal and cardiovascular functions. Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), drugs that disrupt RAAS function, are effective in treating hypertension and offer other renoprotective effects independent of blood pressure (BP) reduction. As our understanding of RAAS physiology and the feedback mechanisms of ACE inhibition and angiotensin receptor blockade have improved, questions have been raised as to whether combination ACEI/ARB therapy is warranted in certain patients with incomplete angiotensin blockade on one agent. In this review, we discuss the rationale for combination ACEI/ARB therapy and summarize the results of key adult studies and the limited pediatric literature that have investigated this therapeutic approach. We additionally review novel therapies that have been developed over the past decade as alternative approaches to combination ACEI/ARB therapy, or that may be potentially used in combination with ACEIs or ARBs, in which further adult and pediatric studies are needed.

The association of post-lung transplant acute kidney injury with mortality is independent of primary graft dysfunction: A cohort study

BACKGROUND

Prior studies of post-lung transplant acute kidney injury (AKI) have not accounted for confounding effects of primary graft dysfunction (PGD). We sought to test the impact of PGD on AKI risk factors and on the association of AKI with mortality.

METHODS

We included patients transplanted at the University of Pennsylvania from 2005-12, defined AKI using consensus criteria during transplant hospitalization, and defined PGD as grade 3 at 48-72 hours. We used multivariable logistic regression to test the impact of PGD on AKI risk factors and Cox models to test association of AKI with one-year mortality adjusting for PGD and other confounders.

RESULTS

Of 299 patients, 188 (62.9%) developed AKI with 142 (75%) cases occurring by postoperative day 4. In multivariable models, PGD was strongly associated with AKI (OR 3.76, 95% CI 1.72-8.19, P = .001) but minimally changed associations of other risk factors with AKI. Both AKI (HR 3.64, 95% CI 1.68-7.88, P = .001) and PGD (HR 2.55, 95% CI 1.40-4.64, P = .002) were independently associated with one-year mortality.

CONCLUSIONS

Post-lung transplant AKI risk factors and association of AKI with mortality were independent of PGD. AKI may therefore be a target for improving lung transplant mortality rather than simply an epiphenomenon of PGD.

Association Between Acute Fall in Estimated Glomerular Filtration Rate After Treatment for Primary Aldosteronism and Long-Term Decline in Renal Function

Primary aldosteronism causes renal structural damage after glomerular hyperfiltration, and primary aldosteronism-specific treatment leads to an acute fall in estimated glomerular filtration rate (eGFR). We investigated whether this change affected the long-term eGFR slope in a retrospective cohort from the multicenter Japan Primary Aldosteronism Study. We allocated patients with primary aldosteronism to the adrenalectomy (n=202) and MR (mineralocorticoid receptor) antagonist (n=303) groups based on their treatment history and analyzed the association between the initial eGFR fall and long-term eGFR slope. The increased age, low serum potassium levels, high eGFR, and high plasma aldosterone levels were independent predictors for a large initial eGFR fall in both groups. Our analysis of tertiles based on the initial eGFR fall revealed that in the MR antagonist group, patients with a small initial eGFR fall had a significantly steeper long-term eGFR slope than those with a large initial fall (tertile 1 versus 2, P=0.025; tertile 1 versus 3, P=0.017). These associations were not identified in the adrenalectomy group. Thus, the smaller the acute fall in eGFR by initiation of MR antagonists, the greater was the rate of long-term eGFR decline. While the acute fall in eGFR induced by primary aldosteronism-specific treatment is occasionally a clinical concern, our findings highlight the favorable implications of the acute fall with respect to long-term renal outcomes.

Clinical Efficacy and Safety of Jinshuibao Combined With ACEI/ARB in the Treatment of Diabetic Kidney Disease: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

The present study aims to compare the relative efficacy and safety of jinshuibao (JSB) combined with angiotensinconverting enzyme inhibitors/angiotensin receptor blockers (ACEIs/ARBs) in the treatment of diabetic kidney disease.

METHODS

We searched EMBASE, MEDLINE, PubMed, China National Knowledge Internet, the Chinese Biomedical Database, and Wanfang database for articles from the building of the database to September 2018.

RESULTS

Fifty-one randomized controlled trials with 3,955 participants were included. The meta-analysis indicated that compared with the controls, JSB combined with ACEI/ARB group could remarkably improve the overall response rate (odds ratio 4.91; 95% confidence interval [CI] 3.32-7.25) and reduce 24 h proteinuria (mean difference [MD] -0.16; 95% CI -0.19 to -0.13), urine albumin excretion ratio (MD -28.20; 95% CI -36.30 to -20.11), serum creatinine (MD -13.84; 95% CI -18.01 to -9.68), blood urea nitrogen (MD -1.00; 95% CI -1.36 to -0.63), systolic blood pressure (MD -4.57; 95% CI -6.78 to -2.37), diastolic blood pressure (MD -3.96; 95% CI -5.73 to -2.19), fasting blood glucose (MD -0.85; 95% CI -1.45 to -0.24), hemoglobin A1c (MD -0.52; 95% CI -0.83 to -0.21), serum total cholesterol (MD -0.53; 95% CI -0.86 to -0.20), and triglyceride (MD -0.53; 95% CI -0.55 to -0.51).

CONCLUSIONS

JSB combined with ACEI/ARB in the treatment of diabetic kidney disease is superior to the single application of ACEI/ARB.

Patterns of Antihypertensive Drug Utilization among US Adults with Diabetes and Comorbid Hypertension: The National Health and Nutrition Examination Survey 1999-2014

BACKGROUND

Diabetes and hypertension are the 2 leading risk factors for suboptimal cardiovascular and renal outcomes. These 2 conditions often coexist and can benefit from antihypertensive therapy, which may lead to blood pressure control and reduced risk for nephropathy (as evidenced by albuminuria).

OBJECTIVE

To quantify the trends of antihypertensive drug use and to assess the impact of antihypertensive treatment on the prevalence of blood pressure control and albuminuria, among US adults with coexisting diabetes and hypertension.

METHODS

In this serial cross-sectional study, we analyzed data from the 1999-2014 National Health and Nutrition Examination Survey (N = 3586). We determine the prevalence of antihypertensive use, drug classes used, and their association with blood pressure control and albuminuria.

RESULTS

During the study period, the study population experienced substantial increase in antihypertensive treatment (from 84.6% in 1999-2002 to 90.1% in 2011-2014, Ptrend  < .01) and blood pressure control (from 37.1% to 46.9%, Ptrend  < .01) and decrease in albuminuria (from 39.1% to 31.3%, Ptrend  = .02). These trends were particularly pronounced in the subgroups using angiotensin-converting-enzyme inhibitors or angiotensin II receptor blockers. In multivariate analysis, Blacks, Hispanics, and males were found more likely to have albuminuria than their respective counterparts. Achieving blood pressure control (odds ratio = 0.40, 95% confidence interval [CI]: 0.32-0.49) was associated with lower rates of albuminuria.

CONCLUSION AND RELEVANCE

Despite continued improvement in antihypertensive therapy, the burden of uncontrolled blood pressure and albuminuria remains substantial among US adults with diabetes and hypertension. Tailoring pharmacotherapy based on patient characteristics and comorbidities is needed to further improve these outcomes.

Angiotensin-converting enzyme inhibitors or angiotensin receptor blocker monotherapy retard deterioration of renal function in Taiwanese chronic kidney disease population

It remains unclear how different uses of angiotensin-converting inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) influence the progression of chronic kidney disease (CKD). This study explored CKD progression in a multicentre, longitudinal cohort study that included 2639 patients with CKD stage 1–5 and hypertension. Patients treated with ACEI or ARB for ≥90 days during a 6-mo period comprised the study group, or no treatment, comprised the control group. The study group was subdivided on the basis of treatment: ACEI monotherapy or ARB monotherapy. Progression of renal deterioration was defined by an average eGFR decline of more than 5 mL/min/1.73 m²/yr or the commencement of dialysis. With at least 1-year follow up, a progression of renal deterioration was demonstrated in 29.70% of the control group and 25.09% of the study group. Patients in the study group had significantly reduced progression of CKD with adjusted odds ratio 0.79 (95% confidence interval: 0.63–0.99). However, when ACEI monotherapy and ARB monotherapy were analyzed separately, none of their associations with CKD progression was statistically significant. In conclusion, ACEI or ARB monotherapy may retard the deterioration of renal function among patients with CKD and hypertension.

Decreased expression of transforming growth factor-β1 and α-smooth muscle actin contributes to the protection of lotensin against chronic renal failure in rats

Background: Lotensin has been shown to have a protective function in the early stage of chronic renal failure. However, its role in the intermediate and late stages of chronic renal failure remains largely unknown. The present study aimed to investigate the role and underlying mechanism of lotensin in advanced chronic kidney disease.

Methods: Female Wistar rats were randomly divided into three groups (n = 10): sham group, 5/6 nephrectomy (5/6 Nx) group, and lotensin group (oral administration of lotensin for 9 weeks following 5/6 Nx). Rats were sacrificed and pathological parameters were measured. Western blot assay and immunohistochemical staining were performed to detect the expression of transforming growth factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA) in kidney tissues.

Results: Compared to the 5/6 Nx group, lotensin administration significantly decreased 5/6 Nx-induced elevation in blood urea nitrogen, serum creatinine and 24-h urinary protein excretion (UPE) rates, but markedly increased red blood cell count, plasma albumin and hemoglobin levels, along with improved renal morphology. Mechanistically, lotensin dramatically downregulated the renal expression of TGF-β1 and α-SMA induced by 5/6 Nx.

Conclusions: Lotensin protects against advanced chronic kidney disease in rats with 5/6 Nx through the downregulation of TGF-β1 and α-SMA.

Effect of renin-angiotensin-aldosterone system blocking agents on progression of glomerulopathy in sickle cell disease

Although renin-angiotensin-aldosterone system (RAAS) blocking agents decrease albuminuria in short-term studies, there is no evidence confirming their long-term efficacy in sickle cell disease (SCD). In a single-centre, retrospective study, we evaluated the long-term effect of RAAS blocking agents on proteinuria and declining estimated glomerular filtration rates (eGFR). Eighty-six patients on RAAS blocking agents for proteinuria, followed for a median of 2·28 years, were compared with 68 patients with proteinuria followed for 2·24 years who were not receiving such treatment. The log odds of proteinuria decreased over time in patients on RAAS blocking agents (β: -0·23, P = 0·03) and in the non-treatment group (β: -0·54, P < 0·0001), but was not statistically different between both groups (β: 0·31, P = 0·063). The eGFR declined over time in patients on RAAS blocking agents (β: -2·78, P < 0·0001) and in those not on such treatment (β: -4·7, P < 0·0001), and was statistically different between both groups (β: 1·9, P = 0·0002). Baseline eGFR was associated with mortality (Hazard rato: 0·97, P < 0·0001), but RAAS blocking agents had no significant effect on mortality. These data suggest that RAAS blockade may slow the loss of kidney function in SCD.

Combining streptozotocin and unilateral nephrectomy is an effective method for inducing experimental diabetic nephropathy in the 'resistant' C57Bl/6J mouse strain

Diabetic nephropathy (DN) is the leading cause of chronic kidney disease. Animal models are essential tools for designing new strategies to prevent DN. C57Bl/6 (B6) mice are widely used for transgenic mouse models, but are relatively resistant to DN. This study aims to identify the most effective method to induce DN in a type 1 (T1D) and a type 2 diabetes (T2D) model in B6 mice. For T1D-induced DN, mice were fed a control diet, and randomised to streptozotocin (STZ) alone, STZ+unilateral nephrectomy (UNx), or vehicle/sham. For T2D-induced DN, mice were fed a western (high fat) diet, and randomised to either STZ alone, STZ+UNx, UNx alone, or vehicle/sham. Mice subjected to a control diet with STZ +UNx developed albuminuria, glomerular lesions, thickening of the glomerular basement membrane, and tubular injury. Mice on control diet and STZ developed only mild renal lesions. Furthermore, kidneys from mice on a western diet were hardly affected by diabetes, UNx or the combination. We conclude that STZ combined with UNx is the most effective model to induce T1D-induced DN in B6 mice. In our hands, combining western diet and STZ treatment with or without UNx did not result in a T2D-induced DN model in B6 mice.

Factors associated with residual urine volume preservation in patients undergoing hemodialysis for end-stage kidney disease in Kinshasa

BACKGROUND

Decreased residual urine volume (RUV) is associated with higher mortality in hemodialysis (HD). However, few studies have examined RUV in patients on HD in Sub-Saharan Africa. The aim of this study was to identify predictors of RUV among incident hemodialysis patients in Kinshasa.

METHODS

This historical cohort study enrolled 250 patients with ESRD undergoing hemodialysis between January 2007 and July 2013 in two hemodialysis centers in Kinshasa. RUV were collected over 24 h at the initiation of HD and 6 and 12 months later during the interdialytic period. We compared the baseline characteristics of the patients according to their initial RUV (≤ 500 ml/day vs >  500 ml/day) using Student's t, Mann-Whitney U and Chi2 tests. Linear mixed-effects models were used to search for predictors of decreased RUV by adding potentially predictive baseline covariates of the evolution of RUV to the effect of time: age, sex, diabetes mellitus, hypertension, diastolic blood pressure, diuretics, angiotensin conversion enzyme inhibitors (ACEI), angiotensin receptor blockers, hypovolemia, chronic tubulointerstitial nephropathy, left ventricular hypertrophy and initial hemodialysis characteristic. A value of p < 0.05 was considered the threshold of statistical significance.

RESULTS

The majority of hemodialysis patients were male (68.8%, sex ratio 2.2), with a mean age of 52.5 ± 12.3 years. The population's RUV decreased with time, but with a slight deceleration. The mean RUV values were 680 ± 537 ml/day, 558 ± 442 ml/day and 499 ± 475 ml/day, respectively, at the initiation of HD and at 6 and 12 months later. The use of ACEI at the initiation of HD (beta coefficient 219.5, p < 0.001) and the presence of chronic tubulointerstitial nephropathy (beta coefficient 291.8, p = 0.007) were significantly associated with RUV preservation over time. In contrast, the presence of left ventricular hypertrophy at the initiation of HD was significantly associated with decreased RUV over time (beta coefficient - 133.9, p = 0.029).

CONCLUSIONS

Among incident hemodialysis patients, the use of ACEI, the presence of chronic tubulointerstitial nephropathy and reduced left ventricular hypertrophy are associated with greater RUV preservation in the first year of dialysis.

Histamine H4 receptor antagonism prevents the progression of diabetic nephropathy in male DBA2/J mice

Due to the incidence of diabetes and the related morbidity of diabetic nephropathy, identification of new therapeutic strategies represents a priority. In the last few decades new and growing evidence on the possible role of histamine in diabetes has been provided. In particular, the histamine receptor H₄R is emerging as a new promising pharmacological target for diabetic nephropathy. The aim of this study was to evaluate the efficacy of selective H₄R antagonism by JNJ39758979 on the prevention of diabetic nephropathy progression in a murine model of diabetes induced by streptozotocin injection. JNJ39758979 (25, 50, 100 mg/kg/day p.o.) was administered for 15 weeks starting from the onset of diabetes. Functional parameters were monitored throughout the experimental period. JNJ39758979 did not significantly affect glycaemic status or body weight. The urine analysis indicated a dose-dependent inhibitory effect of JNJ39758979 on Albumin-Creatinine-Ratio, the Creatinine Clearance, the 24 h urine volume, and pH urine acidification (P < 0.05). The beneficial effects of JNJ39758979 on renal function paralleled comparable effects on renal morphological integrity. These effects were sustained by a significant immune infiltration and fibrosis reduction. Notably, megalin and sodium-hydrogen-exchanger 3 expression levels were preserved. Our data suggest that the H₄R participates in diabetic nephropathy progression through both a direct effect on tubular reabsorption and an indirect action on renal tissue architecture via inflammatory cell recruitment. Therefore, H₄R antagonism emerges as a possible new multi-mechanism therapeutic approach to counteract development of diabetic nephropathy development.

The Renin-Angiotensin-Aldosterone System as a Therapeutic Target in Late Injury Caused by Ischemia-Reperfusion

Ischemia-reperfusion (I/R) injury is a well-known phenomenon that involves different pathophysiological processes. Connection in diverse systems of survival brings about cellular dysfunction or even apoptosis. One of the survival systems of the cells, to the assault caused by ischemia, is the activation of the renin-angiotensin-aldosterone system (also known as an axis), which is focused on activating diverse signaling pathways to favor adaptation to the decrease in metabolic supports caused by the hypoxia. In trying to adapt to the I/R event, great changes occur that unchain cellular dysfunction with the capacity to lead to cell death, which translates into a poor prognosis due to the progression of dysfunction of the cellular activity. The search for the understanding of the diverse therapeutic alternatives in molecular coupling could favor the prognosis and evolution of patients who are subject to the I/R process.

Angiotensin receptor blockers are associated with lower mortality than ACE inhibitors in predialytic stage 5 chronic kidney disease: A nationwide study of therapy with renin-angiotensin system blockade

Dual renin angiotensin system (RAS) blockade using angiotensin-receptor blockers (ARBs) in combination with angiotensin converting enzyme inhibitors (ACEIs) is reported to improve proteinuria in both diabetic and non-diabetic patients. However, its renoprotective effect and safety remain uncertain in patients with advanced chronic kidney disease (CKD). From January 1, 2000 through June 30, 2009, we enrolled 14,117 pre-dialytic stage 5 CKD patients with serum creatinine >6mg/dL and hematocrit <28% under the treatment with erythropoiesis stimulating agents and RAS blockade. We used Cox proportional hazards regression models to estimate the hazard ratios (HRs) against the commencement of long-term dialysis and all-cause mortality for ACEI/ARB users. Over a median follow-up of 7 months, 9,867 patients (69.9%) required long-term dialysis and 2,805 (19.9%) died before progression to end-stage renal disease requiring dialysis. In comparison with the ARB-only users, dual blockade with ACEIs and ARBs was associated with a significantly higher risk of (1) death in all CKD patients (HR = 1.49, [95%CI, 1.30-1.71]; P = 0.02) and in diabetic subgroup (HR = 1.58, [95%CI, 1.34-1.86]; P = 0.02); (2) composite endpoint of long-term dialysis or death in diabetic subgroup (HR = 1.10, [95%CI, 1.01-1.20]; P = 0.04); (3) hyperkalemia-associated hospitalization in non-diabetic subgroup (HR, 2.74, [95%CI, 1.05-7.15]; P = 0.04). However, ACEIs users were associated with higher mortality than ARBs users in all CKD patients (HR = 1.17, [95%CI, 1.07-1.27]; P = 0.03) and in diabetic subgroup (HR = 1.32, [95%CI, 1.18-1.48]; P = 0.03). Monotherapy of RAS blockade, especially ARB, is more effective and safer than dual RAS blockade in pre-dialytic stage 5 CKD patients.

Losartan therapy decreases albuminuria with stable glomerular filtration and permselectivity in sickle cell anemia

Sickle cell nephropathy begins with hyperfiltration and microalbuminuria and may progress to renal failure. The aim of this study was to determine the effects of losartan on glomerular function and albumin excretion in sickle cell anemia (SCA). Individuals with SCA on hydroxyurea with persistent albuminuria were enrolled in a 1-year study of losartan. Glomerular filtration rate (GFR) measured by iohexol clearance, albumin excretion rate (AER), and fractional clearance of dextran were assessed at baseline, short-term (1-2month), and long-term (≥12month) intervals. Twelve subjects (6 microalbuminuria, 6 macroalbuminuria) completed short-term studies; 8 completed long-term studies. Baseline GFR was 112ml/min/1.73m² (71-147ml/min/1.73m²). AER decreased significantly at the short-term (median decrease -134 mcg/min, p=0.0063). GFR was not significantly-different at short-term or long-term intervals. Dextran clearance improved for diameters smaller than albumin (<36Å) but not larger sizes. Losartan therapy for ≥1year in sickle nephropathy results in lower albumin excretion with stable GFR. Filtration of neutral molecules ≥36Å was not changed by losartan, suggesting that the effect of losartan is a mechanism other than alteration of glomerular filtration size-selectivity.

Effects of RAAS Inhibitors in Patients with Kidney Disease

Proteinuria and decline of renal function are associated with progression of kidney disease. The Renin Angiotensin Aldosterone System (RAAS) plays an important role in blood pressure regulation, fluid volume, and sodium balance. Overactivity of RAAS contributes to the pathogenesis of a variety of clinical conditions including progress of chronic kidney disease (CKD). This review summarizes the use of RAAS inhibitors as dual therapy or monotherapy in different stages of kidney disease. Experimental and clinical studies have demonstrated RAAS inhibitors prevent proteinuria, kidney fibrosis and slow decline of renal function and thus play a protective role in both early and end stages of kidney disease. While combination use of RAAS inhibitors showed higher efficiency compared with monotherapy, it is also associated with higher incidence of adverse events. Besides ACEI/ARBs, more mechanism research of mineralocorticoid receptor antagonists in kidney disease should be performed.

Angiotensin II synergizes with BAFF to promote atheroprotective regulatory B cells

Angiotensin II (AngII) promotes hypertension, atherogenesis, vascular aneurysm and impairs post-ischemic cardiac remodeling through concerted roles on vascular cells, monocytes and T lymphocytes. However, the role of AngII in B lymphocyte responses is largely unexplored. Here, we show that chronic B cell depletion (Baffr deficiency) significantly reduces atherosclerosis in Apoe^−/− mice infused with AngII. While adoptive transfer of B cells in Apoe^−/−/Baffr^−/− mice reversed atheroprotection in the absence of AngII, infusion of AngII in B cell replenished Apoe^−/−/Baffr^−/− mice unexpectedly prevented the progression of atherosclerosis. Atheroprotection observed in these mice was associated with a significant increase in regulatory CD1d^hiCD5⁺ B cells, which produced high levels of interleukin (IL)-10 (B10 cells). Replenishment of Apoe^−/−/Baffr^−/− mice with Il10^−/− B cells reversed AngII-induced B cell-dependent atheroprotection, thus highlighting a protective role of IL-10⁺ regulatory B cells in this setting. Transfer of AngII type 1A receptor deficient (Agtr1a^−/−) B cells into Apoe^−/−/Baffr^−/− mice substantially reduced the production of IL-10 by B cells and prevented the AngII-dependent atheroprotective B cell phenotype. Consistent with the in vivo data, AngII synergized with BAFF to induce IL-10 production by B cells in vitro via AngII type 1A receptor. Our data demonstrate a previously unknown synergy between AngII and BAFF in inducing IL-10 production by B cells, resulting in atheroprotection.

Angiotensin II synergizes with BAFF to promote atheroprotective regulatory B cells

Angiotensin II (AngII) promotes hypertension, atherogenesis, vascular aneurysm and impairs post-ischemic cardiac remodeling through concerted roles on vascular cells, monocytes and T lymphocytes. However, the role of AngII in B lymphocyte responses is largely unexplored. Here, we show that chronic B cell depletion (Baffr deficiency) significantly reduces atherosclerosis in Apoe ^-/- mice infused with AngII. While adoptive transfer of B cells in Apoe ^-/- /Baffr ^-/- mice reversed atheroprotection in the absence of AngII, infusion of AngII in B cell replenished Apoe ^-/- /Baffr ^-/- mice unexpectedly prevented the progression of atherosclerosis. Atheroprotection observed in these mice was associated with a significant increase in regulatory CD1d^hiCD5⁺ B cells, which produced high levels of interleukin (IL)-10 (B10 cells). Replenishment of Apoe ^-/- /Baffr ^-/- mice with Il10 ^-/- B cells reversed AngII-induced B cell-dependent atheroprotection, thus highlighting a protective role of IL-10⁺ regulatory B cells in this setting. Transfer of AngII type 1A receptor deficient (Agtr1a ^-/-) B cells into Apoe ^-/- /Baffr ^-/- mice substantially reduced the production of IL-10 by B cells and prevented the AngII-dependent atheroprotective B cell phenotype. Consistent with the in vivo data, AngII synergized with BAFF to induce IL-10 production by B cells in vitro via AngII type 1A receptor. Our data demonstrate a previously unknown synergy between AngII and BAFF in inducing IL-10 production by B cells, resulting in atheroprotection.

Hepatocyte growth factor inhibits tubular epithelial‑myofibroblast transdifferentiation by suppression of angiotensin II via the JAK2/STAT3 signaling pathway

Tubular epithelial‑myofibroblast transdifferentiation (TEMT) is important in the development of chronic renal failure. The present study investigated whether hepatocyte growth factor (HGF) inhibits TEMT, and whether this function may be associated with the inhibition of angiotensin II (AngII) and the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway. Human HK‑2 kidney proximal tubular cells were divided into 4 groups and treated with AngII (1x10‑6 M), HGF (8x10‑3 M), AngII plus HGF or control conditions, followed by an assessment of apoptosis induction and the expression levels of α‑smooth muscle actin (α‑SMA), which is a marker of TEMT. as well as the activation level of JAK2, phosphorylated (p)‑JAK2, STAT3 and p‑STAT3 signaling pathways. In HK‑2 cells, α‑SMA mRNA and protein expression levels increased following treatment with AngII, however, decreased expression was observed following exposure to HGF. HGF counteracted the AngII‑induced increase in the expression of α‑SMA in HK‑2 cells. Similar expression profiles were observed for the phosphorylated forms of JAK2 and STAT3, indicating the possible involvement of this signaling pathway. The results demonstrated that treatment of cells with AngII was associated with the induction of apoptosis when compared with the control. By contrast, treatment with HGF attenuated AngII‑induced apoptosis. The results suggested that HGF may inhibit TEMT by inhibiting AngII through the JAK2/STAT3 signaling pathway in HK‑2 cells and HGF may prevent apoptosis induced by AngII. The present study provides a basis for understanding the mechanisms involved in the inhibition of TEMT by HGF, which requires further investigation.

Association of renal function with clinical parameters and conditions in a longitudinal population-based epidemiological study

The aim of the present study was to examine the association of renal function with clinical parameters and conditions in the general population. Study subjects comprised 6,027 community-dwelling individuals who were recruited to the Inabe Health and Longevity Study: A longitudinal genetic epidemiological study of atherosclerotic, cardiovascular and metabolic diseases. The cutoff value, which was used to divide the subjects into those with normal and those with low estimated glomerular filtration rate (eGFR), was 60 ml/min/1.73 m2. Bonferroni's correction was applied to establish the statistical significance of the association. Longitudinal analysis using the generalized linear mixed-effect model, following adjustments for age and gender, revealed that the eGFR was significantly associated (P<0.0017) with serum levels of triglycerides, low-density lipoprotein cholesterol, uric acid, blood glycosylated hemoglobin content, fasting plasma glucose and body mass index. These parameters decreased curvilinearly with increases in eGFR. Furthermore, eGFR correlated positively with serum levels of high-density lipoprotein (HDL) cholesterol. Longitudinal analysis using the generalized estimating equation following adjustment for age and gender indicated a significant association (P<0.0024) between eGFR and prevalence of hypertension, type 2 diabetes mellitus, hypo-HDL cholesterolemia, hyperuricemia and obesity. Thus, low eGFR results in detrimental effects on various clinical parameters and conditions, resulting in increased risk of hypertension, dyslipidemia, type 2 diabetes mellitus, hyperuricemia and obesity.

Immunologic Effects of the Renin-Angiotensin System

Inappropriate activation of the renin-angiotensin system (RAS) exacerbates renal and vascular injury. Accordingly, treatment with global RAS antagonists attenuates cardiovascular risk and slows the progression of proteinuric kidney disease. By reducing BP, RAS inhibitors limit secondary immune activation responding to hemodynamic injury in the target organ. However, RAS activation in hematopoietic cells has immunologic effects that diverge from those of RAS stimulation in the kidney and vasculature. In preclinical studies, activating type 1 angiotensin (AT₁) receptors in T lymphocytes and myeloid cells blunts the polarization of these cells toward proinflammatory phenotypes, protecting the kidney from hypertensive injury and fibrosis. These endogenous functions of immune AT₁ receptors temper the pathogenic actions of renal and vascular AT₁ receptors during hypertension. By counteracting the effects of AT₁ receptor stimulation in the target organ, exogenous administration of AT₂ receptor agonists or angiotensin 1-7 analogs may similarly limit inflammatory injury to the heart and kidney. Moreover, although angiotensin II is the classic effector molecule of the RAS, several RAS enzymes affect immune homeostasis independently of canonic angiotensin II generation. Thus, as reviewed here, multiple components of the RAS signaling cascade influence inflammatory cell phenotype and function with unpredictable and context-specific effects on innate and adaptive immunity.

Angiotensin-(1-7) relieved renal injury induced by chronic intermittent hypoxia in rats by reducing inflammation, oxidative stress and fibrosis

We aimed to study the renal injury and hypertension induced by chronic intermittent hypoxia (CIH) and the protective effects mediated by angiotensin 1-7 [Ang(1-7)]. We randomly assigned 32 male Sprague-Dawley rats (body weight 180-200 g) to normoxia control, CIH, Ang(1-7)-treated normoxia, and Ang(1-7)-treated CIH groups. Systolic blood pressure (SBP) was monitored at the start and end of each week. Renal sympathetic nerve activity (RSNA) was recorded. CTGF and TGF-β were detected by immunohistochemistry and western blotting. Tissue parameters of oxidative stress were also determined. In addition, renal levels of interleukin-6, tumor necrosis factor-α, nitrotyrosine, and hypoxia-inducible factor-1α were determined by immunohistochemistry, immunoblotting, and ELISA. TUNEL assay results and cleaved caspase 3 and 12 were also determined. Ang(1-7) induced a reduction in SBP together with a restoration of RSNA in the rat model of CIH. Ang(1-7) treatment also suppressed the production of reactive oxygen species, reduced renal tissue inflammation, ameliorated mesangial expansion, and decreased renal fibrosis. Thus, Ang(1-7) treatment exerted renoprotective effects on CIH-induced renal injury and was associated with a reduction of oxidative stress, inflammation and fibrosis. Ang(1-7) might therefore represent a promising therapy for obstructive sleep apnea-related hypertension and renal injury.

Utilization Study of Antihypertensives in a South Indian Tertiary Care Teaching Hospital and Adherence to Standard Treatment Guidelines

AIM

Hypertension represents a major health problem primarily because of its role in contributing to the initiation and progression of major cardiovascular diseases. Concerns pertaining to hypertension and its sequelae can be substantially addressed and consequent burden of disease reduced by early detection and appropriate therapy of elevated blood pressure. This cross-sectional observational study aims at analyzing the utilization pattern of antihypertensives used for the treatment of hypertension at a tertiary care hospital in perspective of standard treatment guidelines.

MATERIALS AND METHODS

Prescriptions were screened for antihypertensives at the medicine outpatient department of a tertiary care teaching hospital. Medical records of the patients were scrutinized after which 286 prescriptions of patients suffering from hypertension were included. The collected data were sorted and analyzed on the basis of demographic characteristics and comorbidities.

RESULTS

The calcium channel blockers were the most frequently used antihypertensive class of drugs (72.3%). Amlodipine (55.6%) was the single most frequently prescribed antihypertensive agent. The utilization of thiazide diuretics was 9%. Adherence to the National List of Essential Medicines (NLEMs) was 65%. The combination therapy was used more frequently (51.5%) than monotherapy (48.8%). The use of angiotensin-converting enzyme inhibitors/angiotensin 2 receptor blockers (ACE-I/ARB) was 41.4% in diabetes.

CONCLUSIONS

The treatment pattern, in general, conformed to standard treatment guidelines. Few areas, however, need to be addressed such as the underutilization of thiazide diuretics, need for more awareness of drugs from the NLEMs and enhanced use of ACE-I/ARB in diabetic hypertensives.