Cardiovascular disease in patients with renal disease: the role of statins

Differentiation of Diabetes by Pathophysiology, Natural History, and Prognosis

The American Diabetes Association, JDRF, the European Association for the Study of Diabetes, and the American Association of Clinical Endocrinologists convened a research symposium, "The Differentiation of Diabetes by Pathophysiology, Natural History and Prognosis" on 10-12 October 2015. International experts in genetics, immunology, metabolism, endocrinology, and systems biology discussed genetic and environmental determinants of type 1 and type 2 diabetes risk and progression, as well as complications. The participants debated how to determine appropriate therapeutic approaches based on disease pathophysiology and stage and defined remaining research gaps hindering a personalized medical approach for diabetes to drive the field to address these gaps. The authors recommend a structure for data stratification to define the phenotypes and genotypes of subtypes of diabetes that will facilitate individualized treatment.

Shenhua Tablet inhibits mesangial cell proliferation in rats with chronic anti-Thy-1 nephritis

Background

In China, mesangial proliferative glomerulonephritis (MsPGN) is one of the most common kidney diseases. In this study, we treated a rat model of chronic anti-Thy-1 MsPGN with Shenhua Tablet and evaluated whether the tablet was able to protect the kidney function. Thirty-six Wistar rats were randomly divided into six groups: (1) Sham surgery (Sham); (2) anti-Thy-1 nephritis model (Thy-1); (3) anti-Thy-1 nephritis model + irbesartan-treated (Irb); (4) anti-Thy-1 nephritis model + low-dose of Shenhua Tablet (SHL); (5) anti-Thy-1 nephritis model + medium-dose of Shenhua Tablet (SHM); (6) anti-Thy-1 nephritis model + high-dose of Shenhua Tablet (SHH).

Results

Thirteen weeks after drug treatment, urinary proteins were quantified and renal pathological changes were thoroughly examined at the time point of 24 h. Meanwhile, the expression levels of p-Erk1/2, cyclin D1 and p21 at the renal cortex were also tested. The levels of urinary proteins and total cholesterol in the blood were significantly reduced in rats treated with any drug tested in this study. The level of triglyceride was significantly reduced in all three Shenhua Tablet-treated groups. Renal pathomorphological scores were significantly improved in groups of Irb, SHM and SHH. Mesangial cell proliferation was significantly inhibited in any drug-treated group. p-Erk1/2 and cyclin D1 were downregulated whereas p21 was upregulated in the renal cortex.

Conclusions

Our study indicated that Shenhua Tablet is able to inhibit the abnormal proliferation of mesangial cells and to prevent kidney damage, which is likely associated with downregulation of p-Erk1/2 and reduced activity of its downstream target-cyclin D1.

The profile of patients with chronic kidney disease who regularly present at an Australian general practice

BACKGROUND

Chronic kidney disease (CKD) is a common, serious and mostly asymptomatic condition that places considerable burden on the Australian healthcare system. Yet there is limited information on the patients with CKD who present to Australian primary care services, which represent the gateway to specialized care.

METHODS

Data pertaining to 31,897 patients who presented to a general practice in Western Australia, from 1 January 2013 to 30 June 2014 (inclusive), were extracted for review. Data included attendance records, comorbidities, diagnoses, and demographic details. Binary logistic regression was used to compare patients diagnosed with CKD by the consulting general practitioner with those without this diagnosis.

RESULTS

Of the 8629 patients who regularly attended the practice, 184 (2%) were diagnosed with CKD (mean age: 77.7 years; male: 57.1%). The stage of CKD was recorded in only 8.4% of cases. Patients with CKD averaged 11 more consultations in the past 18 months (mean difference 10.8, 95% CI [9.3, 12.3], p < .001). They were also more likely to: be male; be ex-smokers; be widowed; and to have a carer. Their most common comorbidities included acute infections, cerebrovascular or ischemic heart disease, osteopenia or osteoporosis, and cancer; 8.7% had died within the previous year.

CONCLUSIONS

Despite the prevalence of CKD, only one in five cases were recorded within this large practice. This reveals lost opportunities to monitor and manage patients with this chronic and common disease. Although this represents an important finding, this study is limited by the reliance on practice records, some of which were incomplete. Nevertheless, this study reveals two key findings. First, this disease is under-diagnosed and/or under-recorded. Second, patients with CKD have other, potentially unrelated, problems that may warrant attention.

Plasma Nitration of High-Density and Low-Density Lipoproteins in Chronic Kidney Disease Patients Receiving Kidney Transplants

BACKGROUND

Functional abnormalities of high-density lipoprotein (HDL) could contribute to cardiovascular disease in chronic kidney disease patients. We measured a validated marker of HDL dysfunction, nitrated apolipoprotein A-I, in kidney transplant recipients to test the hypothesis that a functioning kidney transplant reduces serum nitrated apoA-I concentrations.

METHODS

Concentrations of nitrated apoA-I and apoB were measured using indirect sandwich ELISA assays on sera collected from each transplant subject before transplantation and at 1, 3, and 12 months after transplantation. Patients were excluded if they have history of diabetes, treatment with lipid-lowering medications or HIV protease inhibitors, prednisone dose > 15 mg/day, nephrotic range proteinuria, serum creatinine > 1.5 mg/dL, or active inflammatory disease. Sera from 18 transplanted patients were analyzed. Four subjects were excluded due to insufficient data. Twelve and eight patients had creatinine < 1.5 mg/dL at 3 and 12 months after transplantation, respectively. RESULTS. Nitrated apoA-I was significantly reduced at 12 months after transplantation (p = 0.039). The decrease in apoA-I nitration was associated with significant reduction in myeloperoxidase (MPO) activity (p = 0.047). In contrast to apoA-I, nitrated apoB was not affected after kidney transplantation.

CONCLUSIONS

Patients with well-functioning grafts had significant reduction in nitrated apoA-I 12 months after kidney transplantation. Further studies are needed in a large cohort to determine if nitrated apoA-I can be used as a valuable marker for cardiovascular risk stratification in chronic kidney disease.

Statins can improve proteinuria and glomerular filtration rate loss in chronic kidney disease patients, further reducing cardiovascular risk. Fact or fiction?

INTRODUCTION

The prevalence of chronic kidney disease (CKD), a risk factor for cardiovascular disease (CVD), is increasing worldwide. Statin treatment, the cornerstone of prevention or treatment of CVD, might have beneficial effects on urine protein excretion and renal function as determined by the glomerular filtration rate, whereas it might protect from acute kidney injury (AKI), mainly due to contrast-induced AKI. These beneficial effects on CKD may not be drug class effects; specific statins at specific doses may help prevent CKD deterioration and reduce CVD risk. We analysed all statin studies that had renal and CVD endpoints as main outcome measures. MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched up to February 2015.

AREAS COVERED

We consider the effects of statins on microalbuminuria, proteinuria, glomerular filtration rate, AKI associated with angiography or percutaneous coronary intervention and on CVD event rates in patients with CKD.

EXPERT OPINION

Current evidence points towards the need to prescribe high-potency statins in patients with CKD, before a major decline in kidney function occurs. This may reduce CVD risk and delay the progress of CKD. Administration of either atorvastatin or rosuvastatin can prevent contrast-induced AKI before angiography or percutaneous coronary intervention. The combination of simvastatin + ezetimibe may decrease vascular events in patients with advanced CKD.

High-density lipoprotein: structural and functional changes under uremic conditions and the therapeutic consequences

High-density lipoprotein (HDL) has attracted interest as a therapeutic target in cardiovascular diseases in recent years. Although many functional mechanisms of the vascular protective effects of HDL have been identified, increasing the HDL plasma level has not been successful in all patient cohorts with increased cardiovascular risk. The composition of the HDL particle is very complex and includes diverse lipids and proteins that can be modified in disease conditions. In patients with chronic kidney disease (CKD), the accumulation of uremic toxins, high oxidative stress, and chronic micro-inflammatory conditions contribute to changes in the HDL composition and may also account for protein/lipid modifications. These conditions are associated with a decreased protective function of HDL. Therefore, the HDL quantity and the functional quality of the particle must be considered. This review summarizes the current knowledge of dyslipidemia in CKD patients, the effects of lipid-modulating therapy, and the structural modifications of HDL that are associated with dysfunction.

Modulation of NADPH oxidase activity by known uraemic retention solutes

BACKGROUND

Uraemia and cardiovascular disease appear to be associated with an increased oxidative burden. One of the key players in the genesis of reactive oxygen species (ROS) is nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Based on initial experiments demonstrating a decreased inhibitory effect on NADPH oxidase activity in the presence of plasma from patients with CKD-5D after dialysis compared with before dialysis, we investigated the effect of 48 known and commercially available uraemic retention solutes on the enzymatic activity of NADPH oxidase.

METHODS

Mononuclear leucocytes isolated from buffy coats of healthy volunteers were isolated, lysed and incubated with NADH in the presence of plasma from healthy controls and patients with CKD-5D. Furthermore, the leucocytes were lysed and incubated in the presence of uraemic retention solute of interest and diphenyleneiodonium chloride (DPI), an inhibitor of NADPH oxidase. The effect on enzymatic activity of NADPH oxidase was quantified within an incubation time of 120 min.

RESULTS

Thirty-nine of the 48 uraemic retention solutes tested had a significant decreasing effect on NADPH oxidase activity. Oxalate has been characterized as the strongest inhibitor of NADPH oxidase (90% of DPI inhibition). Surprisingly, none of the uraemic retention solutes we investigated was found to increase NADPH oxidase activity. Furthermore, plasma from patients with CKD-5D before dialysis caused significantly higher inhibitory effect on NADPH oxidase activity compared with plasma from healthy subjects. However, this effect was significantly decreased in plasma from patients with CKD-5D after dialysis.

CONCLUSIONS

The results of this study show that uraemic retention solutes modulated the activity of the NADPH oxidase. The results of this study might be the basis for the development of inhibitors applicable as drug in the situation of increased oxidative stress.

Cardiovascular complications in diabetic patients undergoing regular hemodialysis: a 5-year observational study

We aimed to study the vascular outcomes in hemodialysis (HD) patients based on their diabetic status. A cohort observational study was conducted among patients undergoing regular HD with a 5-year follow-up. Of the 252 consecutive HD patients, 60% were diabetic. Compared with nondiabetics, diabetics were 11 years older, 4 years lesser on HD, and more likely to have prior cerebrovascular and coronary artery disease (CAD). Overall 5-year follow-up showed that diabetic patients had higher rates of HD vascular accesses (57% vs 41%, P = .01), CAD (64% vs 33%, P = .001), major amputations (8.6% vs 0%, P = .003), and mortality (66% vs 23%, P = .001). On multivariate analysis, independent predictors of mortality included number of vascular accesses in nondiabetics and HD duration, CAD, and peripheral artery disease in diabetic patients. Diabetes mellitus is associated with a significant vascular burden and mortality among HD patients. Moreover, our finding highlights the vascular impact of renal failure and HD.

HMG-CoA reductase inhibitors in chronic kidney disease

The incidence of chronic kidney disease (CKD) is on the rise in the USA. Cardiovascular events are the leading cause of death in this patient population, therefore reducing the risk of these events has become a major focus. The aim of this review is to assess current literature on the use of statins in CKD and end-stage renal disease. Cholesterol reduction is important in preventing the development and progression of coronary heart disease and its negative effects. Statins have been widely studied and proven to reduce cardiovascular risk in the general population. The information gained from trials has been extrapolated to special populations, including CKD, despite these patients often being excluded. However, recent studies have begun to focus on CKD, hemodialysis, and transplant patients and the use of cholesterol-lowering agents and the potential association with decreased cardiovascular events. In addition, due to the unique pharmacokinetic and pharmacodynamic changes that occur in these patients, choosing the appropriate cholesterol-lowering agent becomes important for both safety and efficacy. The complexity of CKD patients is an important consideration when choosing cholesterol-lowering medication. Patients with CKD are often on medications that may interact with many of the cholesterol-lowering agents. Ensuring drug interactions are minimized is essential to the prevention of adverse events from the medications.

Paraoxonase 1 in chronic kidney failure

In this review we summarize the findings from the literature and our own laboratory on the decreased PON1 activity in renal failure, the mechanisms proposed and the effect of interventions. In addition to profound alterations in lipoproteins, reduced serum PON1 activity has been clearly established in the past decade and could contribute to accelerated development of atherosclerosis in ESRD and in HD. PON1 lactonase activity is lower in ESRD patients. Hemodialysis partially restores PON1 lactonase and the other activities. PON1 activity recovery after dialysis suggests that uremic toxins may play a mechanistic role in PON1 inactivation. Lower PON1 activity in CRF patients is associated with low thiol concentration, high CRP, and is beneficially enhanced with vitamin C and flavonoids. Changes in HDL subclasses, namely lower HDL₃ in these patients may also play a role in PON1 lower activity. Future research should focus on: (1) mechanistic studies on causes for low PON1 activity and mass; (2) prospective studies focusing on whether there is an added predictive value in measuring PON1 activity (and PON1 activity in HDL₃) in this patient population; (3) intervention studies attempting to increase PON1 activity.

Glycemic and lipidic profile in diabetic patients undergoing dialysis

OBJECTIVE

The aim of this study is to assess the clinical care pattern and to compare the lipid and glycemic profile in a group of diabetic patients undergoing both hemodialysis (HD) and peritoneal dialysis (PD) and to correlate these data using biomarkers of cardiovascular risk.

SUBJECTS AND METHODS

The first phase consisted in performing a survey on demographic data, questions about the medical team and glycemic control. In the second phase, patients were assessed through laboratorial data on their glycemic and lipid profile at a single center for HD and PD.

RESULTS

91 patients was the total population; 70 patients (77%) answered the survey; 66 patients (94%) considered the nephrologist the physician responsible for caring for their glycemic control. Second phase: 59 patients were assessed, 29 undergoing HD and 30 undergoing PD. Fifty-seven percent of the patients had HbA1c above 7%; the level of glycemic markers in patients undergoing peritoneal dialysis was significantly higher than in patients undergoing hemodialysis: HbA1c (9.37 ± 0.5) vs. (7.37 ± 0.49) p < 0.01; fasting glycemia (170 ± 15) vs. (126 ± 15) mg/dL p < 0.05. We found a positive correlation between HbA1c and hyperfibrinogenemia (r = 0.4437, p < 0.0005).

CONCLUSIONS

The data reveal that glycemic control in diabetic patients undergoing renal replacement therapy (RRT) is neglected. Peritoneal dialysis is related to the worst level of glycemic markers, possibly due to the glucose content in the dialysis solution, and higher levels from HbA1c have a positive correlation with hyperfibrinogenesis in this population.

Association between the changes in renal function and serum uric acid levels during multifactorial intervention and clinical outcome in patients with metabolic syndrome. A post hoc analysis of the ATTEMPT study

AIM

To assess the effects of long-term multifactorial intervention on renal function and serum uric acid (SUA) levels and their association with estimated cardiovascular disease (eCVD) risk and actual CVD events.

METHODS

This prospective, randomized, target-driven study included 1123 subjects (45.6% men, age 45-65 years) with metabolic syndrome (MetS) but without diabetes or CVD. Patients were randomized to multifactorial treatment. Atorvastatin was titrated from 10-80 mg/day aiming at a low density lipoprotein cholesterol (LDL-C) target of <100 mg/dl (group A) or an LDL-C target of <130 mg/dl (group B). Changes in estimated glomerular filtration rate (eGFR) and SUA levels were recorded in all patients and in the subgroup with stage 3 chronic kidney disease (CKD; eGFR = 30-59 ml/min/1.73 m(2); n = 349). We used ANOVA to compare changes within the same group, unpaired Student t-test to compare results between groups at specific time points, and log-rank test to compare event free survival.

RESULTS

The eCVD-risk reduction was greater in group A. In the overall study population, eGFR increased by 3.5% (p < 0.001) and SUA levels fell by 5.6% (p < 0.001). In patients from group A with stage 3 CKD (group A1; n = 172), eGFR increased by 11.1% (p < 0.001) from baseline and by 7.5% (p < 0.001) in group B1 (n = 177; p < 0.001 vs. the change in group A1). The corresponding fall in SUA levels was 10.7% in group A1 (p < 0.001 vs. baseline) and 8.3% in group B1 (p < 0.001 vs. baseline and group A1). These changes were mainly attributed to atorvastatin treatment. Among the CKD stage 3 patients there were no CVD events in group A1, while 6 events occurred in group B1 (p = 0.014).

CONCLUSIONS

Multifactorial intervention in patients with MetS without established CVD improved renal function and reduced SUA levels. These changes were more prominent in stage 3 CKD patients and might have contributed to the reduction in eCVD risk and clinical events. Original study registration number [ClinicalTrials.gov ID: NCT00416741].

The efficacy and safety of the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors in chronic kidney disease, dialysis, and transplant patients

Coronary heart disease (CHD) is the leading cause of death in Western civilizations, in particular in chronic kidney disease (CKD) patients. Serum total cholesterol and LDL have been linked to the development of atherosclerosis and progression to CHD in the general population. However, the reductions of total and LDL cholesterol in the dialysis population have not demonstrated the ability to reduce the morbidity, mortality, and cost burden associated with CHD. The patients at greatest risk include those with pre-existing CHD, a CHD-risk equivalent, or multiple risk factors. However, data in the dialysis population are much less impressive, and the relationship between plasma cholesterol, cholesterol reduction, use of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase, and reduction in incidence of CHD or effect on progression of renal disease have not been proven. Adverse event information from published trials indicates that agents within this class share similar tolerability and adverse event profiles. Hepatic transaminase elevations may occur in 1 to 2% of patients and is dose related. Myalgia, myopathy, and rhabodmyolysis occur infrequently and are more common in kidney transplant patients and patients with CKD. This effect appears to be dose related and may be precipitated by administration with agents that inhibit cytochrome P-450 isoenzymes. Caution should be exercised when coadministering any statin with drugs that metabolize through cytochrome P-450 IIIA-4 in particular fibrates, cyclosporine, and azole antifungals. Elderly patients with CKD are at greater risk of adverse drug reactions, and therefore the lowest possible dose of statins should be used for the treatment of hyperlipidemia.

An update on the lipid nephrotoxicity hypothesis

When the 'lipid nephrotoxicity hypothesis' was proposed in 1982, it brought together several disparate experimental findings in hyperlipidemia and renal disease to suggest that concomitant hyperlipidemia and proteinuria would cause self-perpetuating renal disease once the initial glomerular insult was no longer present. This process would be analogous to atherosclerosis. Since 1982, increasing evidence has supported the hypothesis that lipid abnormalities contribute to both atherosclerosis and glomerulosclerosis. In this Review, we discuss research developments that are relevant to the lipid nephrotoxicity hypothesis. We describe how inflammatory stress accompanying chronic kidney disease modifies lipid homeostasis by increasing cholesterol uptake mediated by lipoprotein receptors, inhibiting cholesterol efflux mediated by the ATP-binding cassette transporter 1 and impairing cholesterol synthesis in peripheral cells. As a result of these events, cholesterol relocates to and accumulates in renal, vascular, hepatic and possibly other tissues. The combination of increased cellular cholesterol influx and reduced efflux causes injury in some tissues and lowers the plasma cholesterol level. In addition, inflammatory stress causes a degree of statin resistance via unknown mechanisms. These phenomena alter traditional understanding of the pathogenesis of lipid-mediated renal and vascular injury and could influence the clinical evaluation of renal and cardiovascular risk and the role of lipid-lowering treatment in affected patients.