Diverse effects of increasing lisinopril doses on lipid abnormalities in chronic nephropathies

Response and survival of dogs with proteinuria (UPC > 2.0) treated with angiotensin converting enzyme inhibitors

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEi) are a recommended treatment for glomerular proteinuria. Frequency of response to ACEi and the association of achieving proposed urine protein-to-creatinine ratio (UPC) targets on survival is unknown.

OBJECTIVES

To determine response rates to ACEi therapy and whether a positive response is associated with improved survival.

ANIMALS

Eighty-five dogs with proteinuria (UPC > 2.0).

METHODS

Retrospective study including dogs (UPC > 2.0) prescribed an ACEi for treatment of proteinuria. Baseline creatinine, albumin, cholesterol, UPC, and systolic blood pressure were recorded, and cases reviewed to track UPC. Treatment response was defined as achieving a UPC of <0.5 or reduction of ≥50% from baseline within 3 months. Outcome data were collected to determine overall and 12-month survival.

RESULTS

Thirty-five (41%) dogs responded to ACEi treatment. Treatment response was statistically associated with both median survival time (664 days [95% confidence interval (CI): 459-869] for responders compared to 177 [95% CI: 131-223] for non-responders) and 12-month survival (79% responders alive compared to 28% non-responders). Baseline azotemia or hypoalbuminemia were also associated with a worse prognosis, with odds ratios of death at 12 months of 5.34 (CI: 1.85-17.32) and 4.51 (CI: 1.66-13.14), respectively. In the 25 dogs with normal baseline creatinine and albumin, response to treatment was associated with 12-month survival (92% responders alive compared to 54% non-responders, P = .04).

CONCLUSIONS AND CLINICAL IMPORTANCE

When the UPC is >2.0, achieving recommended UPC targets within 3 months appears to be associated with a significant survival benefit. Response to treatment is still associated with survival benefit in dogs with less severe disease (no azotemia or hypoalbuminemia).

Treatment With Lisinopril Prevents the Early Progression of Glomerular Injury in Obese Dahl Salt-Sensitive Rats Independent of Lowering Arterial Pressure

Recently, we reported that obese Dahl salt-sensitive leptin receptor mutant (SSLepRmutant) rats develop glomerular injury and progressive proteinuria prior to puberty. Moreover, this early progression of proteinuria was associated with elevations in GFR. Therefore, the current study examined whether treatment with lisinopril to reduce GFR slows the early progression of proteinuria in SSLepRmutant rats prior to puberty. Experiments were performed on 4-week-old SS and SSLepRmutant rats that were either treated with vehicle or lisinopril (20 mg/kg/day, drinking water) for 4 weeks. We did not observe any differences in MAP between SS and SSLepRmutant rats treated with vehicle (148 ± 5 vs. 163 ± 6 mmHg, respectively). Interestingly, chronic treatment with lisinopril markedly reduced MAP in SS rats (111 ± 3 mmHg) but had no effect on MAP in SSLepRmutant rats (155 ± 4 mmHg). Treatment with lisinopril significantly reduced proteinuria in SS and SSLepRmutant rats compared to their vehicle counterparts (19 ± 5 and 258 ± 34 vs. 71 ± 12 and 498 ± 66 mg/day, respectively). Additionally, nephrin excretion was significantly elevated in SSLepRmutant rats versus SS rats, and lisinopril reduced nephrin excretion in both strains. GFR was significantly elevated in SSLepRmutant rats compared to SS rats, and lisinopril treatment reduced GFR in SSLepRmutant rats by 30%. The kidneys from SSLepRmutant rats displayed glomerular injury with increased mesangial expansion and renal inflammation versus SS rats. Chronic treatment with lisinopril significantly decreased glomerular injury and renal inflammation in the SSLepRmutant rats. Overall, these data indicate that inhibiting renal hyperfiltration associated with obesity is beneficial in slowing the early development of glomerular injury and renal inflammation.

Proteinuria converts hepatic heparan sulfate to an effective proprotein convertase subtilisin kexin type 9 enzyme binding partner

Hepatic uptake of triglyceride-rich remnant lipoproteins is mediated by the low-density lipoprotein receptor, a low-density lipoprotein receptor related protein and the heparan sulfate proteoglycan, syndecan-1. Heparan sulfate proteoglycan also mediates low-density lipoprotein receptor degradation by a regulator of cholesterol homeostasis, proprotein convertase subtilisin kexin type 9 (PCSK9), thereby hampering triglyceride-rich remnant lipoproteins uptake. In this study, we investigated the effects of proteinuria on PCSK9, hepatic heparan sulfate proteoglycan and plasma triglyceride-rich remnant lipoproteins. Adriamycin-injected rats developed proteinuria, elevated triglycerides and total cholesterol (all significantly increased). Proteinuria associated with triglycerides and total cholesterol and serum PCSK9 (all significant associations) without loss of the low-density lipoprotein receptor as evidenced by immunofluorescence staining and western blotting. In proteinuric rats, PCSK9 accumulated in sinusoids, whereas in control rats PCSK9 was localized in the cytoplasm of hepatocytes. Molecular profiling revealed that the heparan sulfate side chains of heparan sulfate proteoglycan to be hypersulfated in proteinuric rats. Competition assays revealed sulfation to be a major determinant for PCSK9 binding. PCSK9 partly colocalized with hypersulfated heparan sulfate in proteinuric rats, but not in control rats. Hence, proteinuria induces hypersulfated hepatic heparan sulfate proteoglycans, increasing their affinity to PCSK9. This might impair hepatic triglyceride-rich remnant lipoproteins uptake, causing proteinuria-associated dyslipidemia. Thus, our study reveals PCSK9/heparan sulfate may be a novel target to control dyslipidemia.

Review shows that lipid disorders are associated with endothelial but not renal dysfunction in children

AIM

We undertook this review to assess the effects of lipid metabolism abnormalities on endothelial and renal function in children.

METHODS

A search of relevant literature published in English from January 1988 to May 2018 was performed, and this included randomised controlled trials, observational cohort studies, systematic reviews and case reports.

RESULTS

The search process identified 2324 relevant studies and 29 were finally included. Noninvasive ultrasound markers of endothelial dysfunction, such as flow-mediated dilation and carotid intima-media thickness, were impaired in children with dyslipidaemia. Dietary interventions and statin therapy reversed the effects of dyslipidaemia on endothelial function in children. Most data from adult studies failed to prove a causative relationship between dyslipidaemia and renal disease progression or a beneficial effect of lipid-lowering treatment on renal outcomes. The limited paediatric data did not indicate dyslipidaemia as an independent risk factor for renal dysfunction, which was mainly estimated by cystatin C levels or proteinuria. Therefore, further investigation is needed to clarify a potential relationship.

CONCLUSION

In view of limited available paediatric evidence, dyslipidaemia may be adversely associated with endothelial function. However, the association between lipid metabolism disorders and renal function in childhood needs to be further investigated.

Comparative efficacy of individual renin-angiotensin system inhibitors on major renal outcomes in diabetic kidney disease: a network meta-analysis

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are two drug classes with well-documented renal protective effects. However, whether there is any difference among individual drugs remains unknown. In this study, we aimed to compare the efficacy of individual ACEIs/ARBs on major renal outcomes in adults with diabetic kidney disease (DKD).

METHODS

We conducted a Bayesian-framework network meta-analysis with a random effects model. We searched PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov for clinical trials of ACEIs or ARBs as monotherapy compared with other conventional antihypertensive drugs or placebo. Primary outcomes were end-stage renal disease (ESRD) and albuminuria/proteinuria (including change in albuminuria/proteinuria, progression to macroalbuminuria and remission to normoalbuminuria). Secondary outcome was doubling of serum creatinine levels. We also assessed for hyperkalemia, cough and angioedema/edema. International prospective register of systematic reviews (PROSPERO) registration CRD42016036997.

RESULTS

A total of 100 studies with data for 22 365 DKD patients, the majority of whom had type 2 diabetes, were included. Individual ACEIs and ARBs at goal doses showed no significant differences in ESRD and doubling of serum creatinine levels. They also shared similar effects on albuminuria/proteinuria reduction and progression or remission of albuminuria. When combining three outcomes of albuminuria/proteinuria as a single endpoint, most ACEIs/ARBs consistently showed favorable antiproteinuric effect, with little difference in the possibility of being the superior treatment for improving albuminuria/proteinuria. Primary outcomes did not change substantially in meta-regressions and sensitivity analyses. Findings were limited by lack of dose equivalence and paucity of data for some outcomes.

CONCLUSIONS

Based on the available evidence, individual ACEIs and ARBs at goal doses appeared to have no or little differences in their effect on major renal outcomes.

Efficacy of Traditional Chinese Medicine Regimen Jian Pi Qu Shi Formula for Refractory Patients with Idiopathic Membranous Nephropathy: A Retrospective Case-Series Study

Background

The treatment of adult refractory idiopathic membranous nephropathy with steroid and other immunosuppressant-resistant nephrotic syndromes can be a significant challenge. We evaluated the efficacy and safety of the traditional Chinese medicine Jian Pi Qu Shi Formula (JPQSF) as a promising regimen.

Methods

We analyzed 15 consecutive patients with biopsy-proven idiopathic membranous nephropathy who failed immunosuppressive therapy from October 2013 to January 2017. JPQSF was administered orally two times per day, respectively, in the morning and at night for 6 months. All patients had at least 1 year of follow-up. The primary endpoints included complete or partial remission. Secondary endpoints included change of clinical parameters and adverse events after 12 months of treatment.

Results

After 12 months, complete remission was achieved in 13.3% of patients and partial remission in 66.7%, yielding a response rate of 80%. Proteinuria, serum albumin, and cholesterol were improved significantly (P<0.001, P<0.001, and P<0.05, respectively). After 1 year of treatment, proteinuria (mean ± SD) decreased from 5.93 ± 2.54 g per 24 h to 1.99 ± 1.17 g per 24 h (P<0.001). No serious adverse events occurred during the observation.

Conclusions

JPQSF may be an alternative therapeutic option for steroid and general immunosuppressant-resistant membranous nephrotic syndrome patients, with a favorable safety profile. Larger and longer follow-up studies evaluating this regimen are warranted.

Treatment of membranous nephropathy: time for a paradigm shift

In patients with membranous nephropathy, alkylating agents (cyclophosphamide or chlorambucil) alone or in combination with steroids achieve remission of nephrotic syndrome more effectively than conservative treatment or steroids alone, but can cause myelotoxicity, infections, and cancer. Calcineurin inhibitors can improve proteinuria, but are nephrotoxic. Most patients relapse after treatment withdrawal and can become treatment dependent, which increases the risk of nephrotoxicity. The discovery of nephritogenic autoantibodies against podocyte M-type phospholipase A2 receptor (PLA₂R) and thrombospondin type-1 domain- containing protein 7A (THSD7A) antigens provides a clear pathophysiological rationale for interventions that specifically target B-cell lineages to prevent antibody production and subepithelial deposition. The anti-CD20 monoclonal antibody rituximab is safe and achieves remission of proteinuria in approximately two-thirds of patients with membranous nephropathy. In those with PLA₂R-related disease, remission can be predicted by anti-PLA₂R antibody depletion and relapse by antibody re-emergence into the circulation. Thus, integrated evaluation of serology and proteinuria could guide identification of affected patients and treatment with individually tailored protocols. Nonspecific and toxic immunosuppressive regimens will fall out of use. B-cell modulation by rituximab and second-generation anti-CD20 antibodies (or plasma cell-targeted therapy in anti-CD20 resistant forms of disease) will lead to a novel therapeutic paradigm for patients with membranous nephropathy.

Effect of losartan and spironolactone on triglyceride-rich lipoproteins in diabetic nephropathy

Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs) can improve dyslipidemia in patients with diabetes and albuminuria. Whether combined ACEi+ARB or ACEi+mineralocorticoid receptor blockade improves dyslipidemia is not known. We hypothesized long-term administration of either losartan 100 mg or spironolactone 25 mg once daily added onto lisinopril 80 mg once daily would improve dyslipidemia in diabetic nephropathy (DN). We measured lipid levels, very-low-density (V), intermediate-density (I), low-density (LDL), high-density (HDL) lipoprotein, LDL particle size with their respective cholesterol (C) and apolipoprotein B levels (ApoB), and urine albumin/creatinine ratio (UACR) at 12-week interval during a 48-week randomized, double-blind placebo-controlled trial in 81 patients with DN. Plasma lipids and lipoprotein C were analyzed enzymatically and Apo B was determined chemically. Data were analyzed by mixed model repeated measures. ΔUACR differed among treatment arms (placebo −24.6%, los −38.2%, spiro −51.6%, p=0.02). No correlation existed between ΔUACR and ΔTG or any of the lipid or lipoprotein measurements. Compared with placebo losartan, but not spironolactone, decreased TG (−20.9% vs +34.3%, p<0.01), V+I C(−18.8% vs +21.3%, p<0.01), and V+I-ApoB (−13.2% vs +21%, p<0.01). There were no significant changes in body weight, HbA1c or other lipoprotein variables. We conclude losartan improves dyslipidemia in patients with DN. We speculate the mechanism improved clearance of VLDL and remnant lipoproteins.

Optimal care of lupus nephritis patients

Optimal care of lupus nephritis patients should include the treatment of proteinuria and hypertension, other measures to delay the progression of chronic kidney disease, the vigorous management of cardiovascular risk factors and finally, the treatment of advanced chronic kidney disease and its consequences. These topics are briefly reviewed in the present paper, with particular emphasis on the recent progresses in antiproteinuric treatment.

Rituximab for Severe Membranous Nephropathy: A 6-Month Trial with Extended Follow-Up

Randomized trials of rituximab in primary membranous nephropathy (PMN) have not been conducted. We undertook a multicenter, randomized, controlled trial at 31 French hospitals (NCT01508468). Patients with biopsy-proven PMN and nephrotic syndrome after 6 months of nonimmunosuppressive antiproteinuric treatment (NIAT) were randomly assigned to 6-month therapy with NIAT and 375 mg/m² intravenous rituximab on days 1 and 8 (n=37) or NIAT alone (n=38). Median times to last follow-up were 17.0 (interquartile range, 12.5-24.0) months and 17.0 (interquartile range, 13.0-23.0) months in NIAT-rituximab and NIAT groups, respectively. Primary outcome was a combined end point of complete or partial remission of proteinuria at 6 months. At month 6, 13 (35.1%; 95% confidence interval [95% CI], 19.7 to 50.5) patients in the NIAT-rituximab group and eight (21.1%; 95% CI, 8.1 to 34.0) patients in the NIAT group achieved remission (P=0.21). Rates of antiphospholipase A2 receptor antibody (anti-PLA2R-Ab) depletion in NIAT-rituximab and NIAT groups were 14 of 25 (56%) and one of 23 (4.3%) patients at month 3 (P<0.001) and 13 of 26 (50%) and three of 25 (12%) patients at month 6 (P=0.004), respectively. Eight serious adverse events occurred in each group. During the observational phase, remission rates before change of assigned treatment were 24 of 37 (64.9%) and 13 of 38 (34.2%) patients in NIAT-rituximab and NIAT groups, respectively (P<0.01). Positive effect of rituximab on proteinuria remission occurred after 6 months. These data suggest that PLA2R-Ab levels are early markers of rituximab effect and that addition of rituximab to NIAT does not affect safety.

Assessment of dyslipidemia in pre-dialysis patients in south-west Nigeria

Background:

Majority of chronic kidney disease (CKD) patients are more likely to die of cardiovascular complications before reaching end stage renal disease. The Kidney Disease Outcomes Quality Initiative (K/DOQI) recommends that all CKD patients should be evaluated for dyslipidemia and for treatment to reduce the risk of cardiovascular events.

Patients and Methods:

A cross-sectional case control study to determine the frequency of occurrence of lipid abnormalities in patients with CKD and compare these abnormalities with that of normal controls. A total of 100 patients and 100 controls were recruited for the study. Demographic and clinical data were obtained using structured questionnaire. Weight, height and waist circumference, body mass index (BMI) and blood pressure were also obtained. Subjects had their fasting lipid profile and fasting plasma glucose assayed after overnight fast of 8-14 hours. Low-density lipoprotein (LDL) was obtained using Friedwald formula.

Result:

The study revealed that total cholesterol (TC) was elevated above normal levels in 44% of cases compared with 6% in controls (P < 0.001), with the mean (SD) value of 5.82 ± 3.28 mmol/l for cases compared with 3.9 ± 1.0 mmol/l (P < 0.001) in controls. Low density lipoprotein was elevated in 48% of cases compared with 14% in controls (P < 0.001), with the mean (SD) values of 4.15 ± 2.74 mmol/l and 2.57 ± 0.95 mmol/l for cases and controls, respectively, (P < 0.001). Triglyceride (TG) was elevated above normal level in 26% of cases compared with none in the controls (P < 0.001), with the mean (SD) values of 1.41 ± 1.10 mmol/l and 0.64 ± 0.24 mmol/l for cases and controls, respectively (P < 0.001). All Lipid fractions except HDL also correlated significantly with levels of proteinuria TC (r = 0.345, P = 0.001), TG (r = 0.268, P = 0.011) LDL (r = 0.366, P = 0.001).

Conclusion:

Dyslipidemia is common among patients with CKD. Regular evaluation of all CKD patients for dyslipidemia and treatment need be instituted.

Combined renin angiotensin blockade in childhood steroid-resistant nephrotic syndrome

BACKGROUND

Reduced proteinuria results in delayed deterioration of renal function and remission of proteinuria predicts a good long-term prognosis in steroid-resistant nephrotic syndrome (SRNS). The aim of this study was to analyze the effects of the combined angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker in reducing proteinuria in SRNS.

METHODS

A prospective study of eight patients with SRNS was conducted at the Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University from September 2003 to December 2007. Enalapril was given at 0.1 mg/kg/day and was increased by 0.1 mg/kg/day every 4 weeks up to 0.6 mg/kg/day (maximum 40 mg/day) and 1 mg/kg/day of losartan was added for 4 weeks and stepped up to 2 mg/kg/day (maximum 100 mg/day) for another 4 weeks.

RESULTS

There were five boys (62.5%) and three girls (37.5%). The mean age at diagnosis was 8.3 ± 4.1 years (range 2.05-13 years) and age at enrollment was 11.7 ± 3.8 years (range 6-16 years). Renal histology revealed seven focal segmental glomerulosclerosis and one immunoglobulin M nephropathy. The results showed significant reduction on mean spot urine protein : creatinine ratio from 9.6 ± 2.3 to 3.6 ± 1.6 (P < 0.05) and 24-h urine protein from 182.8 ± 59.6 to 28.7 ± 8.2 mg/m(2) /h (P < 0.05). Urine protein reduction ratio at the end of the study was 50% (P= 0.08). Serum cholesterol, albumin, potassium, blood pressure and renal function had no significant change. No clinical and laboratory side-effects were reported.

CONCLUSION

Combined high-dose angiotensin II receptor blocker to high-dose angiotensin-converting enzyme inhibitor therapy is safe and effective in reducing proteinuria in childhood SRNS. However a large-scale study should be conducted to validate this result.

Possible mechanism of the cardio-renal protective effects of AVE-0991, a non-peptide Mas-receptor agonist, in diabetic rats

HYPOTHESIS

This study was designed to investigate the cardio-renal protective effect of AVE-0991, a non-peptide Mas-receptor agonist, and A-779, a Mas-receptor antagonist, in diabetic rats.

MATERIALS AND METHODS

Wistar rats treated with streptozotocin (50 mg/kg, i.p., once), developed diabetes mellitus after 1 week. After 8 weeks, myocardial functions were assessed by measuring left ventricular developed pressure (LVDP), rate of left ventricular pressure development (dp/dt (max)), rate of left ventricular pressure decay (dp/dt (min)) and left ventricular end diastolic pressure (LVEDP) on an isolated Langendorff's heart preparation. Further, mean arterial blood pressure (MABP) was measured by using the tail-cuff method. Assessment of renal functions and lipid profile was carried out using a spectrophotometer.

RESULTS

The administration of streptozotocin to rats produced persistent hyperglycaemia, dyslipidaemia and hypertension which consequently produced cardiac and renal dysfunction in 8 weeks. AVE0991 treatment produced cardio-renal protective effects, as evidenced by a significant increase in LVDP, dp/dt (max), dp/dt (min) and a significant decrease in LVEDP, BUN, and protein urea. Further, AVE-0991 treatment for the first time has been shown to reduce dyslipidaemia and produced antihyperglycaemic activity in streptozotocin-treated rats. However, MABP and creatinine clearance remained unaffected with AVE-0991 treatment.

CONCLUSIONS

AVE-0991 produced cardio-renal protection possibly by improving glucose and lipid metabolism in diabetic rats, independent of its blood pressure lowering action.

Beneficial effects of angiotensin (1-7) in diabetic rats with cardiomyopathy

OBJECTIVE

This study was designed to investigate the effect of angiotensin (1-7), a Mas receptor agonist, and A-779, a Mas receptor antagonist, in rats with diabetic cardiomyopathy (DC).

METHODS

Rats treated with a single injection of streptozotocin (50 mg/kg, intraperitoneal), developed DC after 8 weeks. The extent of DC was assessed by measuring the left ventricular weight/body weight (LVW/BW) ratio, absolute LVW, left ventricular developed pressure (LVDP), maximum change in left ventricular pressure over time (dp/dtmax), minimum change in left ventricular pressure over time (dp/dtmin), left ventricular (LV) protein content, LV collagen content, lipid profile, and serum nitrite/nitrate concentration. Test drug treatment was given from week 4 to week 8.

RESULTS

Angiotensin (1-7) treatment attenuated DC by significantly increasing LVDP, dp/dtmax, dp/dtmin, serum nitrite/nitrate concentration and significantly decreasing the LVW/BW ratio and LV collagen content. For the first time, this study has documented that endogenous angiotensin (1-7) regulates lipid profile in rats, and that treatment with angiotensin (1-7) significantly attenuates diabetes-induced changes in lipid profile. However, LV protein content and absolute LVW remain unaffected after treatment.

CONCLUSION

Angiotensin (1-7) significantly attenuates DC in rats because of vasodilatory, antiproliferative and anifibrotic properties but also because of a significant decrease in dyslipidemia, the major culprit for cardiac dysfunctions in diabetes.

Potential pharmacodynamic drug-drug interaction between concomitantly administered lisinopril and diclofenac sodium: a call for appropriate management in hypertensive osteoarthritic patients

BACKGROUND

The present study was designed as an open label, multiple-dose, randomized, parallel trial to evaluate the pharmacodynamic drug-drug interaction of lisinopril and concomitantly administered diclofenac sodium in non-diabetic and diabetic, mild to moderate hypertensive, osteoarthritic patients.

METHODS

Post-screening and on inclusion, patients were put on a 2-week washout period and then randomly assigned to either only lisinopril 10 mg or combination of lisinopril 10 mg and diclofenac sodium 100 mg treatments for 8-12 weeks in diseased states of hypertension and osteoarthritis with or without type 2 diabetes mellitus.

RESULTS

The blood pressure (BP) control with lisinopril was reduced by concomitantly administered diclofenac sodium in non-diabetic (SBP: p=0.00002; DBP: p=0.000008) and diabetic (SBP: p=0.002; DBP: p=0.001) patients when compared with the patients receiving lisinopril alone. Insulin sensitivity was improved (p=0.00002) and urinary albumin excretion rate was better controlled (p=0.0096) in lisinopril-treated patients when compared with the combination treatment in diabetic pool. Serum creatinine levels increased significantly in non-diabetic patients (p=0.00004) receiving combination treatment. In addition, creatinine clearance (CLCR) and blood urea nitrogen (BUN) were significantly higher in diabetic (CLCR: p<0.00001; BUN: p=0.0098) as well as in non-diabetic (CLCR: p<0.00001; BUN: p=0.03) patients treated with combination treatment. The alterations in serum electrolytes, reduction in % platelet aggregation activity and improvement in lipid profile was more profound with combination treatment in comparison to lisinopril alone.

CONCLUSIONS

The antihypertensive efficacy and insulin sensitivity improving property of lisinopril along with the renal function might get worse in hypertensive osteoarthritic patients receiving concomitant treatment of oral diclofenac sodium with lisinopril. In addition to this, close monitoring of serum electrolytes is also suggested to rule out any long-term detrimental effect.

Pharmacologic Issues in treating hypertension in CKD

Antihypertensive drugs are prescribed to patients with CKD to slow down the rate of loss of residual kidney function; to reduce proteinuria, when present; and to protect other target organs from damage that is mediated by elevated blood pressure (BP). In most patients, a diuretic and a renin system blocking drug, such as an angiotensin-converting enzyme inhibitor, angiotensin receptor antagonist, or an aldosterone receptor antagonist are used. Often, 3 or more drugs are needed to achieve BP goals. Many drugs are eliminated through the kidney and in some cases dosage reductions are advisable to avoid adverse effects from high levels of medication. This article will review the various classes of antihypertensive drugs used in the management of high BP in patients with CKD, with an emphasis on pitfalls that arise when kidney function is impaired.

Comparison of the influence of angiotensin-converting enzyme inhibitor lisinopril and angiotensin II receptor antagonist losartan in patients with idiopathic membranous nephropathy and nephrotic syndrome

OBJECTIVE

In this prospective study, the effects of an angiotensin-converting enzyme inhibitor [lisinopril (LIS)] and an angiotensin II receptor antagonist [losartan (LOS)] were compared in nephrotic patients with idiopathic membranous nephropathy.

MATERIAL AND METHODS

Twenty-seven patients (13 males, mean age +/- SD 51.3 +/- 15.4 years) were treated with LIS (13 patients, six males, mean age 52.1 +/- 15.3 years) or LOS (14 patients, seven males, mean age 50.5 +/- 15.5 years) for 12 months. At baseline and after the treatment period, serum albumin, total cholesterol, estimated glomerular filtration rate (GFR), 24 h proteinuria and mean arterial pressure were determined.

RESULTS

Proteinuria (g/24 h) was significantly reduced in both groups (LIS from 4.82 +/- 1.26 to 1.75 +/- 0.64, p < 0.0001; LOS from 4.55 +/- 1.09 to 2.54 +/- 1.94, p = 0.002) (all results +/- SD). Serum albumin levels (g/dl) increased significantly in both groups (LIS 2.27 +/- 0.41 to 3.17 +/- 0.63, p < 0.0001; LOS 2.93 +/- 0.40 to 3.55 +/- 0.44, p < 0.0001). GFR (ml/min x 1.73 m(2)) did not change significantly in either group (LIS 55 +/- 17 to 56 +/- 17, p = 0.65; LOS 64 +/- 18 to 59 +/- 16, p = 0.13). Total cholesterol (mg/dl) was significantly reduced only in the lisinopril group (LIS 347 +/- 81 to 266 +/- 64, p < 0.0001; LOS 306 +/- 58 to 263 +/- 77, p = 0.138). Mean arterial pressure (mmHg) was reduced in both groups (LIS 107 +/- 12 to 95 +/- 6, p < 0.0001; LOS 104 +/- 10 to 96 +/- 5, p = 0.003). In the comparison between the two groups, serum albumin levels were higher in the losartan group at baseline (p < 0.0001) and after 12 months (p = 0.029). There were no significant differences between the baseline and end-of-study values for the rest of the studied parameters.

CONCLUSION

Treatment with lisinopril and losartan in nephrotic patients with idiopathic membranous nephropathy results in similar (and significant) effects on renal function, hypoalbuminaemia, proteinuria and blood pressure.

Effects of add-on fluvastatin therapy in patients with chronic proteinuric nephropathy on dual renin-angiotensin system blockade: the ESPLANADE trial

BACKGROUND AND OBJECTIVES

This open, prospective, randomized trial aimed to assess the effects of statins in chronic kidney disease patients on optimized antiproteinuric treatment with combined angiotensin-converting enzyme inhibition and angiotensin receptor blockade.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

After 1-month benazepril therapy followed by 1-month benazepril-valsartan combined therapy (run-in), 186 consenting patients with residual proteinuria >0.5 g/24 h were randomized to 6-month benazepril-valsartan therapy alone or combined with fluvastatin. Between-groups changes in proteinuria (primary outcome), serum lipids, and GFR were compared by ANCOVA. Analyses were blinded and by intention to treat.

RESULTS

During the run-in, proteinuria decreased more on benazepril-valsartan than on benazepril alone. Proteinuria reduction correlated with concomitant reduction in total, LDL, and HDL cholesterol, and apolipoprotein B and apolipoprotein A levels. After randomization, median proteinuria similarly decreased from 1.2 (0.6 to 2.2) to 1.1 (0.5 to 1.7) g/24 h on fluvastatin and from 1.5 (0.8 to 2.7) to 1.0 (0.5 to 2.4) g/24 h on benazapril-valsartan therapy alone. Fluvastatin further reduced total and LDL cholesterol and apolipoprotein B versus benazepril-valsartan alone, but did not affect serum triglycerides and GFR. Treatment was well tolerated.

CONCLUSIONS

In chronic kidney disease patients with residual proteinuria despite combined angiotensin-converting enzyme inhibitor and angiotensin receptor blockade therapy, add-on fluvastatin does not affect urinary proteins, but further reduces serum lipids and is safe. Whether combined angiotensin-converting enzyme inhibitor, angiotensin receptor blockade, and statin therapy may improve cardiovascular outcomes in this high-risk population is worth investigating.

Proteinuria: Increased angiotensin-receptor blocking is not the first option

Candesartan doses in excess of the recommended antihypertensive maxima have been reported to lead to greater reductions of proteinuria than the advised doses. High-dose angiotensin-converting-enzyme inhibitors, however, are at least as effective as high-dose angiotensin blockers and less expensive. Angiotensin-converting-enzyme inhibition is thus the first-line strategy to halt kidney disease progression.

Optimal dose of lisinopril for renoprotection in type 1 diabetic patients with diabetic nephropathy: a randomised crossover trial

AIMS/HYPOTHESIS

The purpose of this study was to evaluate the optimal renoprotective effect of ultrahigh doses of lisinopril, as reflected by short-term changes in urinary albumin excretion rate (UAER), in type 1 diabetic patients with diabetic nephropathy.

METHODS

At the Steno Diabetes Center, 49 type 1 diabetic patients with diabetic nephropathy completed this double-masked randomised crossover trial consisting of an initial washout period followed by three treatment periods each lasting 2 months, where all patients received lisinopril 20, 40 and 60 mg once daily in randomised order in addition to slow-release furosemide. Allocation was concealed by sequentially numbered opaque sealed envelopes. UAER, 24 h ambulatory blood pressure (ABP) and estimated GFR were determined at baseline and after each treatment period.

RESULTS

All 49 patients completed all three treatment periods. Baseline values were: UAER (geometric mean [95% CI]) 362 (240-545) mg/24 h, 24 h ABP (mean [SD]) 142 (14)/74 (8) mmHg and estimated GFR 75 (29) ml min(-1) 1.73 m(-2). Reductions in UAER from baseline were 63%, 71% and 70%, respectively, with the increasing doses of lisinopril (p < 0.001). Compared with lisinopril 20 mg there was a further reduction in UAER of 23% with lisinopril 40 mg and 19% with 60 mg, p < 0.05. ABP was reduced from baseline by 10/5, 13/7 and 12/7 mmHg (p < 0.001 vs baseline, p < 0.05 for diastolic ABP 20 vs 40 mg, otherwise NS between doses). The difference in UAER between 20 and 40 mg lisinopril was significant after adjustment for changes in ABP (p < 0.01). Two patients were excluded from the study because of an increase in plasma creatinine and one because of high BP; otherwise the study medication was well tolerated with few, mild, dose-independent adverse effects.

CONCLUSIONS/INTERPRETATION

Lisinopril 40 mg once daily is generally safe and offers additional reductions in BP and UAER in comparison with the currently recommended dose of 20 mg. Lisinopril 60 mg offers no further beneficial effect.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00118976.

The kidney and hypertension: causes and treatment

Chronic kidney disease is both a cause and a consequence of hypertension. Extracellular volume expansion is an important, if not the most important, contributing factor to hypertension seen in chronic kidney disease. Beyond volume expansion, chronic kidney disease-related hypertension is without truly defining characteristics. Consequently, the sequencing of antihypertensive medications for the patient with chronic kidney disease and hypertension becomes arbitrary. Prescription practice in such patients should be mindful of the need for multiple drug classes with at least one of them being a diuretic. Blood pressure goals in the patient with chronic kidney disease and hypertension are set at lower levels than those for patients with essential hypertension alone. It remains to be determined to what level blood pressure should be lowered in the patient with chronic kidney disease, however.

Membranous nephropathy in the older adult: epidemiology, diagnosis and management

Membranous nephropathy is the most important cause of the nephrotic syndrome in elderly patients (aged >65 years). The clinical presentation is similar in older and younger patients, although elderly patients more often present with renal failure. Notably, glomerular filtration rate (GFR) is usually lower in the elderly due to the physiological decline in GFR after the age of 30 years. Secondary causes, especially malignancies, are more common in older patients with membranous nephropathy. Therefore, elderly patients should undergo a thorough examination to exclude a secondary cause. The prognosis of elderly patients with idiopathic membranous nephropathy is not very different from that of younger patients. All elderly patients should receive symptomatic treatment aimed at reducing hypertension, oedema, proteinuria and hyperlipidaemia. It is recommended that elderly patients with a low serum albumin (<2 g/dL) receive prophylactic anticoagulation because of a high risk for thrombosis. Immunosuppressive therapy should be reserved for elderly patients at high risk of progression to end-stage renal disease because the elderly are particularly prone to the adverse effects and infectious complications of immunosuppressive therapy. High-risk elderly patients are characterised by renal insufficiency (GFR <45 mL/min/1.73m(2)), an increase in serum creatinine of >25% or a severe persistent nephrotic syndrome not responding to symptomatic treatment. In addition, elderly patients with a relatively normal GFR (>or=45 mL/min/1.73m(2)) and high urinary excretion of beta(2)-microglobulin and IgG are also at increased risk of developing end-stage renal disease; however, the deterioration in renal function is usually a slow process. Therefore, such patients benefit from immunosuppressive therapy only if their life expectancy is good. If immunosuppressive therapy is started, first-line treatment consists of prednisone and cyclophosphamide. If cyclophosphamide is contraindicated or fails to induce a remission, ciclosporin could be used. Treatment with ciclosporin should be limited to patients with a relatively normal renal function (GFR >60 mL/min/1.73m(2)) in view of its nephrotoxicity in patients with renal dysfunction.

Albuminuria response to very high-dose valsartan in type 2 diabetes mellitus

OBJECTIVE

Renin-angiotensin system blockade is now standard in the management of the patient with type 2 diabetes mellitus. We aimed to investigate whether high doses of valsartan, an angiotensin receptor blocker, are superior to conventional doses to reduce urinary albumin excretion rates (UAER) in such patients.

PATIENTS AND METHODS

Three hundred and ninety-one hypertensive patients with type 2 diabetes mellitus and UAER 20-700 microg/min were randomized to 160, 320 or 640 mg valsartan. All received valsartan 160 mg for the first 4 weeks. Valsartan dose was then increased in two of three groups for 30 weeks. Overnight urine collections at baseline, 4, 16, and 30 weeks in triplicate were used to assess proteinuria.

RESULTS

Comparable albuminuria reductions occurred in all groups at week 4 (P<0.001). Subsequently, a highly significant albuminuria fall occurred with valsartan 320 and 640 mg (P<0.001) versus a modest additional change with 160 mg (P=0.03). At week 30, twice as many patients returned to normal albuminuria with valsartan 640 mg versus 160 mg (24 versus 12%; P<0.01). High doses were well tolerated, with no dose-related increases in adverse events, including hypotension and hyperkalemia.

CONCLUSION

High doses of valsartan reduced albuminuria more than the more commonly used 160 mg dose, apparently independent of blood pressure. Thus, at least in type 2 diabetes mellitus, higher doses of valsartan are required to optimize tissue protection than for blood pressure control.

Pharmacological management of renal fibrotic disease

Chronic kidney diseases frequently advance to end-stage renal failure, and the number of patients affected is steadily increasing worldwide. At the molecular level, progression of renal insufficiency correlates closely with ongoing pathological matrix protein expansion (i.e., renal fibrosis), in a manner independent of the underlying disorder. Overactivity of the renin-angiotensin system and of the TGF-beta system have been identified as key mediators of kidney matrix accumulation, and are principal targets in the management of chronic renal disease. This review provides a recent overview of the therapeutic options that are clinically established, and of novel molecular strategies that will approach clinical practice in the near future.

Effects of pioglitazone and candesartan on renal fibrosis and the intrarenal plasmin cascade in spontaneously hypercholesterolemic rats

The profibrotic effect of plasminogen activator inhibitor-1 (PAI-1) in renal fibrosis is widely recognized, but its mechanism remains controversial especially in chronic progressive kidney disease. In the present study, pioglitazone (Pio) and candesartan (CD), which are reported to inhibit PAI-1, were administered to spontaneously hypercholesterolemic (SHC) rats, a model of chronic progressive kidney disease. Therapeutic effects and effects on the intrarenal plasmin cascade were examined. Eight-wk-old SHC rats were used as controls. Oral administration of vehicle alone, Pio, or CD was performed starting at 8 wk of age and was continued for 24 wk. The degree of renal fibrosis was evaluated by sirius red staining of kidney sections and by total collagen assay of renal homogenates. The renal PAI-1 protein level was assessed by Western blotting, and plasmin activity was analyzed by chromogenic assay and casein gel zymography. Urinary protein and blood urea nitrogen were significantly increased in the vehicle-treated group, but the increase was attenuated in the Pio- and CD-treated groups. This correlated well with the degree of fibrosis as assessed by sirius red staining and total collagen assay. The PAI-1 protein level was also increased significantly in the vehicle-treated group, and the increase was attenuated in the Pio- and CD-treated groups. Despite the presumed plasmin-inhibitory function of PAI-1, plasmin activity changed in parallel with PAI-1. These results suggest that Pio and CD inhibit PAI-1 and exert renoprotective effects against chronic progressive renal disease, but its action is independent of the regulatory function on plasmin activity.

[Lupus membranous nephropathy]

The systemic lupus erythematosus associated renal hystopathological complexity and its clinical translation, are still a diagnostic challenge with therapeutical implications which, however, include new options in the last few years within the immunosupression compass. The new insights elicited by research work attempt to give some light on renal biopsy performance, its relationship with the arrogated clinical spectrum, its prognosis and on the lupus nephropathy new treatments currently under ongoing clinical trials, some of them showing encouraging results. The lupus membranous nephropathy, recognized as an anatomopathological entity more than 4 decades ago, means a specific pattern in the whole renal lupus histologycal range and, in many aspects, an etiopathogenic enigma.

Hypertension, Renal Disease, and Drug Considerations

The incidence of chronic kidney disease is steadily increasing in the United States. The magnitude of this problem is such that virtually all health care providers are being called upon to manage these patients. The interplay between chronic kidney disease and drug therapy is complex in that the kidney is both a target for drug effect as well as a moderator of drug elimination. Renal drug elimination occurs by filtration, secretion, and/or metabolism. For renally-cleared compounds, drug clearance typically falls in tandem with the loss of renal function. This process is noteworthy for drug accumulation when the glomerular filtration rate approaches the 30-cc/min range. The kidney is a target for drug effect in relationship to blood pressure and protein excretion. Angiotensin-converting enzyme inhibitor and angiotensin receptor blocker therapy (usually given along with a diuretic) are the drug classes that have been shown to be effective for reduction in both blood pressure and protein excretion in the chronic kidney disease patient. A number of questions still remain unanswered in the pharmacotherapy of chronic kidney disease, including the optimal dose for these drugs as well as what represents the most favorable achieved blood pressure.

Renoprotection of Optimal Antiproteinuric Doses (ROAD) Study: a randomized controlled study of benazepril and losartan in chronic renal insufficiency

The Renoprotection of Optimal Antiproteinuric Doses (ROAD) study was performed to determine whether titration of benazepril or losartan to optimal antiproteinuric doses would safely improve the renal outcome in chronic renal insufficiency. A total of 360 patients who did not have diabetes and had proteinuria and chronic renal insufficiency were randomly assigned to four groups. Patients received open-label treatment with a conventional dosage of benazepril (10 mg/d), individual uptitration of benazepril (median 20 mg/d; range 10 to 40), a conventional dosage of losartan (50 mg/d), or individual uptitration of losartan (median 100 mg/d; range 50 to 200). Uptitration was performed to optimal antiproteinuric and tolerated dosages, and then these dosages were maintained. Median follow-up was 3.7 yr. The primary end point was time to the composite of a doubling of the serum creatinine, ESRD, or death. Secondary end points included changes in the level of proteinuria and the rate of progression of renal disease. Compared with the conventional dosages, optimal antiproteinuric dosages of benazepril and losartan that were achieved through uptitration were associated with a 51 and 53% reduction in the risk for the primary end point (P = 0.028 and 0.022, respectively). Optimal antiproteinuric dosages of benazepril and losartan, at comparable BP control, achieved a greater reduction in both proteinuria and the rate of decline in renal function compared with their conventional dosages. There was no significant difference for the overall incidence of major adverse events between groups that were given conventional and optimal dosages in both arms. It is concluded that uptitration of benazepril or losartan against proteinuria conferred further benefit on renal outcome in patients who did not have diabetes and had proteinuria and renal insufficiency.

The effect of statins on preservation of kidney function in patients with coronary artery disease

PURPOSE OF REVIEW

This paper outlines evidence for the putative renal benefits of statins in people with vascular disease.

RECENT FINDINGS

The Greek Atorvastatin and Coronary Heart Disease study showed a modest improvement in kidney function over 4 years among 800 atorvastatin recipients (12%), significantly better than the decrease in kidney function (4%) in 800 placebo recipients. A secondary analysis of the Cholesterol and Recurrent Events trial suggested that pravastatin reduced the rate of kidney function loss to a greater extent in participants with dipstick-positive proteinuria (P < 0.001) and lower levels of renal function at baseline (P = 0.04). A larger post-hoc analysis from this group found that pravastatin modestly reduced the risk of acute renal failure (RR 0.60, 95% CI 0.41-0.86), but not the risk of a 25% decline in kidney function from baseline (RR 0.94, 95% CI 0.88-1.01). In the group with lower baseline kidney function (glomerular filtration rate <60 ml/min/1.73 m(2)) and proteinuria on dipstick urinalysis (n = 249), pravastatin recipients were less likely to experience a 25% or greater decrease in glomerular filtration rate (12.5% versus 19.9%) or acute renal failure (3.2% versus 8.7%).

SUMMARY

Statins may reduce the rate of kidney function loss in people with cardiovascular disease, although the clinical significance of this effect is unclear. Future studies are required before statins can be recommended solely to protect renal function.

Beneficial impact of spironolactone on nephrotic range albuminuria in diabetic nephropathy

Reduction of nephrotic range albuminuria is associated with markedly improved renal and cardiovascular outcome in patients with diabetic nephropathy. Aldosterone has been suggested to play a role in the progression of diabetic nephropathy. We therefore aimed to evaluate the short-term effect of aldosterone antagonism with spironolactone on nephrotic range albuminuria and blood pressure in diabetic nephropathy. Twenty Caucasian patients with diabetic nephropathy and nephrotic range albuminuria (>2500 mg/24 h) despite recommended antihypertensive treatment completed this double-masked, randomized crossover trial. Patients were treated in random order with spironolactone 25 mg once daily and matched placebo for 2 months, on top of ongoing antihypertensive treatment, including an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker in maximally recommended doses. Median (range) number of antihypertensive drugs was 3 (2-5). After each treatment period, albuminuria, 24-h ambulatory blood pressure, and glomerular filtration rate (GFR) were determined. Spironolactone on top of recommended renoprotective treatment induced a 32% (95% confidence interval (CI): 21-42%) reduction in albuminuria from (geometric mean (95% CI)) 3718 (2910-4749) mg/24 h on placebo treatment (P<0.001). There was a significant reduction in 24-h blood pressure of 6 (2-10)/4 (2-6) mm Hg and day blood pressure of 7 (3-12)/5 (3-7) mm Hg (P<0.01), whereas night blood pressure remained unchanged. Spironolactone induced an insignificant reversible reduction in GFR of 3 ml/min/1.73 m2 from 64 (27) ml/min/1.73 m2. No patients were excluded due to adverse events. Our results suggest that spironolactone treatment on top of recommended renoprotective treatment including maximal renin-angiotensin system blockade may offer additional renoprotection in patients with diabetic nephropathy and nephrotic range albuminuria.

Cellular cholesterol efflux to plasma from proteinuric patients is elevated and remains unaffected by antiproteinuric treatment

BACKGROUND

Lipid derangements are assumed to contribute to the elevated cardiovascular risk in proteinuric patients. The impact of proteinuria on reverse cholesterol transport (RCT) is unknown. The first step in RCT, cellular cholesterol efflux to plasma, may be altered in proteinuria, consequent to changes in pre-beta high-density lipoprotein (HDL) formation and plasma phospholipid transfer protein (PLTP) activity.

METHODS

In six non-diabetic male patients with nephrotic-range proteinuria and 12 matched healthy men, plasma (apo)lipoproteins, pre-beta HDL formation, PLTP activity as well as the ability of plasma to promote cholesterol efflux out of cultured human skin fibroblasts were determined. These variables were also measured in response to antiproteinuric treatment, consisting of single and dual RAAS blockade by losartan and lisinopril.

RESULTS

Plasma total cholesterol (P<0.05), triglycerides (P<0.05), apolipoprotein (apo) A-I (P<0.001), apo B (P<0.001), PLTP activity (P<0.005) and pre-beta HDL formation (P<0.001) were higher in proteinuric patients. Cellular cholesterol efflux to plasma from proteinuric patients was 41% higher than to plasma from healthy subjects (P<0.001). Reduction of proteinuria from 5.0 to 1.4 g/day by dual RAAS blockade was associated with a 23% reduction in plasma apo B levels (P<0.05). Pre-beta HDL formation and plasma PLTP activity did not change significantly. Combined antiproteinuric treatment did not reduce the elevated cellular cholesterol efflux.

CONCLUSION

Cellular cholesterol efflux to plasma from patients with nephrotic-range proteinuria is enhanced, in conjunction with elevated pre-beta HDL formation and plasma PLTP activity. These changes may attenuate the cardiovascular risk associated with proteinuria-associated hyperlipidaemia. Antiproteinuric therapy lowers plasma apo B, but does not affect cell-derived cholesterol efflux, suggesting that this therapy beneficially affects cardiovascular risk in proteinuric patients.

Risk factors for thromboembolic events in renal failure

OBJECTIVES

To determine whether prior thromboembolic events (TE) influence current measures of hemostasis, inflammation and oxidative stress in a population at high cardiovascular risk.

BACKGROUND

Renal failure patients demonstrate a remarkably elevated incidence of TE.

METHODS

Relationships between plasma test results and prior TE history were studied in 78 diabetic and 23 non-diabetic patients with renal failure. TE were defined as myocardial infarction, stroke or vascular surgery.

RESULTS

Markers for inflammation (interleukin (IL)-6, C reactive protein (CRP)), thrombosis (fibrinogen, low molecular weight (LMW) fibrinogen, factor VII, viscosity), fibrinolysis (fibrinolytic activity, plasminogen activator inhibitor (PAI)), endothelial/platelet activity (P-selectin, von Willebrand factor (vWf)) and oxidative stress (antibody to oxidized low-density lipoprotein (LDL), advanced glycated end products) were significantly different from a healthy control population. Dialysis patients with diabetes were twice as likely to have sustained a TE (58 vs. 30%, p = 0.032). Those patients in the total group with levels above the median for IL-6 (p = 0.045), and CRP (p < 0.017) were more likely to have sustained a TE than those with levels below the median. Those diabetic patients with levels above the median for CRP were more likely to have a prior history of TE (p < 0.021). For non-diabetic patients, levels above the median of IL-6 were associated with a prior history of TE (p = 0.027). Multiple correlations for factors of inflammation, hemostasis and oxidative stress indicate that these mechanisms are not independent of one another.

CONCLUSION

Prior TE was associated with markers of inflammation a relationship that may influence the interpretation of these tests which are strongly interrelated in patients at high cardiovascular risk.

Dyslipidemia and nephrotic syndrome: Recent advances

Patients with nephrotic syndrome (NS) have one of the most pronounced secondary changes in lipoprotein metabolism known, and the magnitude of the changes correlates with the severity of the disease. These changes are of a quantitative as well as a qualitative nature. All apolipoprotein B (apo B)-containing lipoproteins, such as very-low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), and lipoprotein(a) [Lp(a)], are elevated in nephrotic syndrome. High-density lipoproteins (HDL) are reported to be unchanged or reduced. In addition to these quantitative changes, the lipoprotein composition is markedly changed, with a higher ratio of cholesterol to triglycerides in the apo B-containing lipoproteins and an increase in the proportion of cholesterol, cholesterol ester, and phospholipids compared with proteins. Also apolipoproteins show major changes, with an increase in apolipoprotein A-I, A-IV, B, C, and E. Particularly the changes in apo C-II, which is an activator of the enzyme lipoprotein lipase (LPL), and apo C-III, an inhibitor of LPL, with an increase of the C-III to C-II ratio, might contribute to the impaired lipoprotein catabolism in NS. The mechanisms for these changes in lipoprotein metabolism are discussed in this review as far as they are known. Furthermore, the tremendous elevations of Lp(a) in nephrotic syndrome and its primary and secondary causes are reviewed. Primary causes became recently apparent by a significantly higher frequency of low-molecular-weight apo(a) phenotypes in patients compared with controls. The secondary causes were shown by an increase of Lp(a) in all apo(a) isoform groups. Because Lp(a) is an LDL-like particle that is usually included in the measured or calculated LDL cholesterol fraction, the influence of the extremely high Lp(a) levels in NS on the measurement of LDL cholesterol is discussed.

Combination therapy with ACE inhibitors and angiotensin II receptor blockers to halt progression of chronic renal disease: Pathophysiology and indications

It is no a secret that we are confronted by an alarmingly increasing number of patients with progressive renal disease. There is ample evidence for the notion that angiotensin II (Ang II) is a major culprit in progression. The vasopeptide Ang II turned out to have also multiple nonhemodynamic pathophysiologic actions on the kidney, including proinflammatory and profibrogenic effects. Diverse complex Ang II generating systems have been identified, including specifically local tissue-specific renin-angiotensin systems (RAS). For example, proximal tubular cells have all components required for a functional RAS capable of synthesizing Ang II. On the other hand, Ang II is not the only effector of the RAS and other peptides generated by the RAS influence renal function and structure as well. Moreover, the discoveries that Ang II can be generated by enzymes other than angiotensin-converting enzyme (ACE) and that Ang II and other RAS derived peptides bind to various receptors with different functional consequences have further added to the complexity of this system. Several major clinical trials have clearly shown that ACE inhibitor treatment slows the progression of renal diseases, including in diabetic nephropathy. Well-controlled studies demonstrated that this effect is in part independent of blood pressure control. More recently, with Ang II type 1 receptor (AT(1)) receptor antagonists a similarly protective effect on renal function was seen in patients with type 2 diabetes. Neither ACE inhibitor treatment nor AT(1) receptor blockade completely abrogate progression of renal disease. A recently introduced novel therapeutic approach is combination treatment comprising both ACE inhibitor and AT(1) receptor antagonists. The rationale for this approach is based on several considerations. Small-scale clinical studies, mainly of crossover design, documented that combination therapy is more potent in reducing proteinuria in patients with different chronic renal diseases. Blood pressure as an important confounder was, however, significantly lower in the majority of this studies in the combination treatment arms compared to the respective monotherapies. In a recent prospective study Japanese authors avoided this confounder and demonstrated that combination therapy reduced hard end-points (end stage renal failure or doubling of serum creatinine concentration) by 50% compared to the respective monotherapies. This effect could not be explained by a more pronounced reduction of blood pressure in the combination therapy group. Although these results are encouraging, administration of combination therapy should be reserved currently to special high risk groups. Further studies are necessary to confirm these promising results. It is possible that combination therapy may increase the risk of hyperkalemia, particularly when with coadministered with medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) or spironolactone. In our opinion patients with proteinuria >1 g/day despite optimal blood pressure control under RAS-blocking monotherapy are a high-risk group which will presumably benefit from combination therapy.

Lipid oxidative stress and the anti-inflammatory properties of statins and ACE inhibitors

Observational studies in different populations indicate a positive relationship between dyslipidemia, cardiovascular events, and kidney disease progression. Patients with chronic renal diseases usually present with conditions (inflammation, oxidative stress) that can induce quantitative and qualitative changes in lipoprotein composition, making these particles more atherogenic. Several large randomized trials have shown that lowering cholesterol with statins reduces coronary mortality and morbidity across a wide range of cholesterol levels. Moreover, statins ameliorated renal function and structure in experimental models of progressive renal disease as well as in patients with proteinuric disease. It has been hypothesized that statins may directly modulate intracellular signaling systems involved in cellular proliferation, inflammatory, and fibrogenic responses. In addition, studies in animals have shown that the mevalonate pathway also may be involved in the regulation of the renin-angiotensin system, providing the rationale for the use of statins in combination with angiotensin-converting enzyme inhibitors and/or angiotensin II receptor antagonists, 2 classes of drugs that have evidenced beneficial effects in different forms of renal diseases. Preliminary studies have shown that a multidrug approach may induce remission of proteinuria, lessen renal injury, and protect from loss of function in those patients whose condition does not fully respond to a single treatment.

Angiotensin-converting enzyme inhibition and angiotensin II antagonism in nondiabetic chronic nephropathies

Angiotensin II (A II), the main effector of the renin angiotensin system (RAS), plays a central role in the hemodynamic and nonhemodynamic mechanisms of chronic renal disease and is currently the main target of interventions aimed to prevent the onset and progression of chronic nephropathies to end-stage renal disease (ESRD). In addition, to ameliorate glomerular hyperfiltration and size selectivity, reduce protein traffic and prevent glomerular and tubulointerstitial toxicity of ultrafiltered proteins, RAS inhibitors also limit the direct nephrotoxic effects of A II. Thus, both angiotension-converting enzyme (ACE) inhibitors (ACEi) and A II antagonists (ATA) exert a specific nephroprotective effect in both experimental and human chronic renal disease. This effect is time-dependent and is observed across degrees of renal insufficiency. Forced ACEi or ATA uptitration above doses recommended to control arterial hypertension and combined treatment with both agents allow optimization of A II inhibition and maximization of renoprotection. Multifactorial interventions combining RAS inhibition to treatments targeted also to non-RAS mechanisms could even achieve regression of glomerulosclerosis and chronic tubulointerstitial injury. Studies are needed to assess whether renal damage can be reverted to such a point that renal function could be fully prevented from worsening, and possibly improvement. The economic impact of even a partial improvement would be enormous. Moreover, chronic renal insufficiency is an independent risk factor for cardiovascular disease, and effective nephroprotection could also decrease the excess cardiovascular morbidity and mortality associated with chronic nephropathies. In patients with renal insufficiency, ACEi are even more cardioprotective than in those without and are well tolerated. Thus, RAS inhibitor therapy should be offered to all renal patients without specific contraindications, including those closer to renal replacement therapy.

Beneficial impact on cardiovascular risk factors by dual blockade of the renin-angiotensin system in diabetic nephropathy

BACKGROUND

Patients with diabetic nephropathy have a high risk of cardiovascular disease and end-stage renal disease. Dual blockade of the renin-angiotensin system (RAS) with both ACE inhibitors (ACE-I) and angiotensin II receptor blockers may offer therapeutic advantages.

METHODS

Based on three double-blind randomized cross-over trials, we analyzed the short-term effects of dual blockade of the RAS on cardiovascular surrogate end points in 51 type 1 diabetic patients with diabetic nephropathy.

RESULTS

Compared to ACE-I, dual blockade of the RAS decreased albuminuria 37% from 558 mg/24 hour, and lowered 24-hour blood pressure 7/5 mm Hg from 137/76 mm Hg (P < 0.01). In addition, dual blockade lowered total and LDL-cholesterol 0.3 from 5.4 mmol/L and 3.1 mmol/L, respectively (P < or = 0.01). The antialbuminuric response to dual blockade of the RAS was influenced by the insertion (I)/deletion (D) polymorphism in the ACE gene.

CONCLUSION

Dual blockade of the RAS may offer additional cardiovascular and renal protection in type 1 diabetic patients with diabetic nephropathy. Determination of the ACE/ID genotype may help identify patients particularly sensitive to such therapy.

AT-1 receptor blockade prevents proteinuria, renal failure, hyperlipidemia, and glomerulosclerosis in the Imai rat

BACKGROUND

The Imai rat is a model of spontaneous focal glomerulosclerosis which leads to nephrotic syndrome, hyperlipidemia, hypertension, and progressive renal failure. We evaluated the effects of angiotensin II receptor type 1 (AT-1)blockade, and compared the results with the effects of the administration of hypolipidemic treatment with a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor. All treatments were started at 10 weeks of age when the rats were already proteinuric and continued for 6 months when rats were sacrificed.

METHODS

The following groups (N= 6 each) were studied: (1) control Sprague-Dawley rats, 34 weeks old; (2) Imai group that received vehicle; (3) Imai + angiotensin II receptor blockade (ARB) group that received olmesartan (10 mg/kg/day by gastric gavage); (4) Imai + prava group, that received pravastatin (20 mg/kg/day by gastric gavage); and (5) Imai + ARB + prava group that received both ARB and pravastatin. Lipid profile, renal function, and structure were assessed at 6 months.

RESULTS

As expected, the untreated Imai rats exhibited heavy proteinuria, hypoalbuminemia, hypertension, renal insufficiency, marked glomerulosclerosis, tubulointerstitial inflammation, and profound hyperlipidemia. Pravastatin treatment alone led to a significant, but partial improvement of hyperlipidemia and renal disease. The ARB treatment alone or in combination with pravastatin resulted in normalization of the blood pressure, urinary protein excretion, plasma cholesterol, triglycerides, low-density lipoproteins (LDLs), very low-density lipoproteins (VLDLs), and albumin concentrations and renal function. Significant glomerulosclerosis was prevented and tubulointerstitial injury and immune cell infiltration were reduced by long-term AT-1 blockade.

CONCLUSION

The study revealed that long-term AT-1 blockade corrects proteinuria, hyperlipidemia, and nephropathy in this model of spontaneous glomerulosclerosis.

Phenotypic heterogeneity in pediatric autosomal dominant polycystic kidney disease at first presentation: a single-center, 20-year review

BACKGROUND

The presentation of autosomal dominant polycystic kidney disease (ADPKD) in childhood provides an insight into comorbidities and potential areas for interventions and investigation.

METHODS

Phenotypic heterogeneity at the time of first presentation was studied with respect to age of diagnosis, mode of presentation, parental inheritance pattern, renal function, associated hypertension, and hyperlipidemia. Fifty-five children (median age of presentation, 8.7 years; 27% < 1 year) with ADPKD from 44 families followed up between March 1983 and March 2003 were reviewed. The diagnosis was based on family history and ultrasound confirmation of cysts. Progression of renal disease was followed over the study period (mean duration of follow-up, 4.9 years).

RESULTS

A family history of ADPKD was known at presentation in 89%, which precipitated the screening diagnostic imaging in 59% of these children. Maternal inheritance was displayed in 51%, whereas 5% had no known family history of ADPKD. Bilateral renal findings were present in 78%. Hypertension (>95(th) percentile for age) was present in 22%, and hyperlipidemia was present in 54%. Renal function was not significantly diminished in 98% of patients with creatinine clearance > or =3rd percentile for age, and 7% had persistent proteinuria (>150 mg/d). No subjects had hepatic, splenic, or pancreatic cysts on ultrasound scan. A subpopulation of 10 patients had features of ADPKD dating back to prenatal ultrasound scans. All prenatal cases were characterized by bilateral renal findings, 90% had a known family history of ADPKD at the time of presentation, and 89% of these patients displayed maternal inheritance. Follow-up studies showed a persistence of hyperlipidemia despite pharmacotherapeutic treatment of hypertension, infrequent proteinuria, and sustained renal function in most patients.

CONCLUSION

The results of this study show that many children at the time of first presentation have a significant prevalence of modifiable risk factors: hypertension, proteinuria, and hyperlipidemia, in the face of normal renal function. The results also show a unique presentation existing in prenatal subjects.

Slowing the Progression of Adult Chronic Kidney Disease

When kidney disease of any aetiology results in substantial loss of nephrons, a common clinical syndrome, characterised by hypertension, proteinuria and a progressive decline in renal function, ensues. This observation suggests that common mechanisms may contribute to progressive renal injury and that therapeutic interventions that inhibit these common pathways may afford renal protection. Research to date has identified several mechanisms that may contribute to progressive renal injury including glomerular haemodynamic changes, multiple effects of angiotensin II and detrimental effects of excessive filtration of plasma proteins by injured glomeruli. Clinical trials over the past decade have identified several interventions that are effective in slowing the rate of progression of chronic kidney disease (CKD). The use of ACE inhibitors, angiotensin receptor antagonists or a combination of the two should be regarded as fundamental to any therapy for slowing the rate of CKD progression. Hypertension should be treated aggressively to achieve a blood pressure target of < 130/80 mm Hg. Reduction of proteinuria to < 0.5 g/day should be regarded as an independent therapeutic goal. Although inconclusive, there is some evidence to support moderate dietary protein restriction to 0.6 g/kg/day in appropriate patients. Hyperlipidaemia may contribute to CKD progression and should be treated to reduce cardiovascular risk and potentially improve renal protection. Smoking cessation should be encouraged and, where necessary, assisted. Among diabetic patients tight glycaemic control should be achieved (glycosylated haemoglobin < 7%). These interventions are simple and relatively inexpensive. If applied to all patients with CKD they will result in substantial slowing of renal function decline in many patients and thereby reduce the number who progress to end-stage renal disease and require renal replacement therapy.

Enalapril dosage in steroid-resistant nephrotic syndrome

We have examined, in a randomized crossover trial, the antiproteinuric effect of treatment with low- (0.2 mg/kg daily) and high-dose (0.6 mg/kg daily) enalapril in 25 consecutive patients with steroid-resistant nephrotic syndrome (SRNS). Patients in group A ( n=11) received enalapril at low doses for 8 weeks, followed by 2 weeks of washout and then at high doses for 8 weeks. Those in group B ( n=14) initially received enalapril at high and then low doses. Patients continued to receive treatment with tapering doses of prednisolone; none received concomitant therapy with daily oral or intravenous steroids, alkylating agents, cyclosporine, non-steroidal anti-inflammatory drugs, and other antihypertensive medications. The urine albumin-to-creatinine (Ua/Uc) ratio and the percentage reduction were determined for each phase of therapy. Baseline clinical, biochemical, and histological features were comparable in the two groups. In the first phase, treatment with low-dose enalapril (group A) resulted in median 34.8% Ua/Uc reduction compared with 62.9% with high doses (group B) ( P<0.01). High-dose enalapril was associated with a significant reduction in Ua/Uc ratio in both groups. The combined median Ua/Uc (95% confidence interval) reduction in the low-dose phase was 33% (-10.3% to 72.4%) and in the high-dose 52% (15.4%-70.4%) ( P<0.05). The median Ua/Uc ratio at the end of 20 weeks was 1.1 and 1.8 in groups A and B, respectively ( P>0.05). Systolic and diastolic blood pressure reductions were similar in both groups. No period or carry-over effect was found. Prolonged treatment with enalapril thus resulted in a dose-related reduction in nephrotic-range proteinuria. Titration of the dose of enalapril may be a useful strategy for achieving substantial reduction of proteinuria in children with SRNS.