Residual Proteinuria Research Articles

#2817 Preliminary results of dapagliflozin in inactive lupus nephritis cross-over randomized trial

Abstract Background and Aims Sodium-glucose co-transporter 2 (SGLT2) inhibitors slow the progression of chronic kidney disease (CKD). Lupus nephritis (LN) patients in remission may continue with residual proteinuria due to scars and hyperfiltration. However, LN patients were excluded from the main trials with SGLT2 inhibitors. This trial aims to assess the effect and safety of dapagliflozin in inactive LN patients with residual proteinuria. Method For this cross-over randomized trial, we include adult patients with LN class III, IV (±V) without active nephritis but with proteinuria >500 mg/24 h or UPC > 200 mg/g and eGFR ≥ 20 ml/min, in the maintenance treatment with a RAAS and mycophenolate mofetil (<2g/day) in stable a dose for at least four weeks before the randomization. We excluded patients with other etiologies of CKD, those with active LN lesions on the recent biopsy (AI>2), use of induction therapy in the last 12 months (cyclophosphamide, mycophenolate mofetil >2g/day and calcineurin inhibitors) and prednisone dose ≥ 20 mg/day. Due to safety issues, we excluded patients with recurrent urinary infections (>3 times/year). Those included were randomized to receive dapagliflozin 10 mg on top of standard of care therapy (SoC) or not. After 24 weeks the groups were switched and those without dapagliflozin received it for the next 24 weeks. Primary endpoint is reduction of proteinuria compared to baseline at 6 and 12 months. Secondary endpoints are sustained reduction of eGFR>30%; occurrence of hypotension symptoms; and number of infections on dapagliflozin treatment versus exclusive SoC therapy. The sample size was calculated for 28 patients enrolled providing 80% power to detect a 25% relative risk reduction in proteinuria (α level of 0.05). Results From 97 screened class III, IV (± V) LN patients under maintenance therapy, we excluded 67 due to active nephritis, low proteinuria or low eGFR. We included 30 patients that were randomized 14 to start the treatment with dapagliflozin on top of SoC and 16 to remain with the usual therapy for 24 weeks. Six patients were excluded from the analysis due to new LN flare or lost to follow-up. We analyzed the data of 12 patients in the initial Dapa + SoC and 12 patients in the initial SoC group after 3 (n = 21), 6 (n = 18), 9 (n = 14) and 12 (n = 12) months. Patients in initial Dapa group had a significant decrease in proteinuria after 6 months (1159 to 882 mg/day; p = 0.017) but increased to 1105 mg/day 6 months after the drug withdrawal (Fig. 1A). This preliminary analysis shows a significant reduction in the proteinuria of –35.8% in patients after 6 mo of dapagliflozin as opposed to an increase in 7.2% for those in the SoC therapy at the end of a 6 mo period, p = 0.02 (Fig. 1C). The drug was well tolerated, but 4 (33.3%) of the patients reported hypotension symptoms during the first days of dapagliflozin. There was one case of urinary infection in each group, but in the same patient. Conclusion Preliminary results show a significant reduction in residual proteinuria in patients with inactive LN with dapagliflozin without an increase in infections.

#525 SGLT2 inhibition in non-diabetic CKD: results in experimental lupus nephritis

Abstract Background and Aims Sodium glucose cotransporter type 2 inhibitors (SGLT2i) potently attenuate cardiovascular morbidity and progression of CKD in patients with type 2 diabetes. It has been proposed that SGLT2 inhibition may also elicit renoprotective effects in non-diabetic CKD. The aim of this work is to evaluate whether the treatment with an SGLT2i improves kidney disease progression in a mouse model of lupus nephritis (LN). Method We performed a single center randomized controlled preclinical trial using female MRLlpr/lpr mice. The animals were randomly assigned to (1) vehicle or (2) empagliflozin (EMP, 10 mg/kg/day) treatment once signs of active systemic lupus erythematosus (SLE) appeared: proteinuria >100 mg/dL (++ in reactive strips) or lymphadenopathy in minimum 2 bilateral sites with proteinuria >30 mg/dL (+ in reactive strips). We included 13 mice per group that were treated during 4 weeks. Empagliflozin was given as an admix into standard chow diet. Reduction of urinary albumin to creatine ratio (UACR) was considered the primary endpoint whereas glomerular filtration rate (GFR), renal histology (LN activity/chronicity index, glomerulosclerosis, interstitial fibrosis) and SLE markers (total serum IgG, anti-dsDNA IgG, glomerular IgG deposits, lymph node weight, spleen weight) were considered secondary endpoints. Results After 4 weeks of treatment, no significant differences in fasting blood glucose levels were found between the experimental groups. As expected, empagliflozin administration notably inhibited SGLT2 in the tubular cells demonstrated by a significant increase of urinary glucose (p < 0.0001). This is consistent with the increased water intake observed in MRLlpr/lpr mice treated with empagliflozin (p < 0.0001). At the end of the experiment, vehicle treated MRLlpr/lpr mice showed a significant increase in UACR (p = 0.0012) consistent with LN progression that was not attenuated by empagliflozin. In line, empagliflozin did not modify GFR and LN activity/chronicity indexes, glomerulosclerosis or interstitial fibrosis in kidney. Finally, regarding SLE markers, 4-weeks empagliflozin treatment was not able to decrease total serum IgG, anti-dsDNA IgG, glomerular IgG deposits or lymph node weight. Only spleen weight was significantly decreased in empagliflozin treated MRLlpr/lpr mice (p = 0.003). Conclusion In our experimental setting, empagliflozin treatment reduced spleen weight suggesting a protective role in SLE in MRLlpr/lpr mice. However, empagliflozin did not modify LN progression in MRLlpr/lpr mice probably because the acute LN phase. It is expected that the positive effect in terms of reducing proteinuria will be observed in patients with LN and residual proteinuria

Role of carotid-femoral (aortic) pulse wave velocity measurement in the evaluation of cardiovascular risk in children with idiopathic nephrotic syndrome

Introduction and objective: The study was aimed to evaluate carotid-femoral (aortic) pulse wave velocity (cfPWV) in children with idiopathic nephrotic syndrome. Materials and methods: A total of 48 children with idiopathic nephrotic syndrome were enrolled in the study, including 35 patients in acute phase and 32 in remission. In 19 patients, measurements were performed twice: in relapse and in remission. The control group consisted of 22 healthy children. In all children, cfPWV measurements were performed. Selected clinical, biochemical parameters and fetuin-A concentrations were determined. Results: The patients with idiopathic nephrotic syndrome had significantly higher cfPWV both in relapse and in remission, as compared to the control group. Fetuin-A levels were significantly lower in both phases of the disease than in the healthy controls. cfPWV in relapse positively correlated with body weight, body mass index, systolic, diastolic, mean and pulse pressure. cfPWV in remission positively correlated with body weight, residual proteinuria, and total and low-density lipoproteins cholesterol. Systolic blood pressure in relapse, body weight, and total cholesterol in remission were found to be independent risk factors for increased cfPWV. Total cholesterol in remission was an independent risk factor for an increase of cfPWV to height rate. Conclusions: Increased cfPWV in children with idiopathic nephrotic syndrome indicates the possibility of premature cardiovascular complications. Significant effects of the modifiable risk factors, such as arterial pressure, body weight and disturbances of lipid metabolism, on arterial stiffness may contribute to early diagnostic and therapeutic interventions to improve the prognosis in patients with idiopathic nephrotic syndrome. Measurements of cfPWV may be useful in the assessment of cardiovascular risk in children with idiopathic nephrotic syndrome.

#5217 PROTOCOL AND PRELIMINARY RESULTS OF DAPAGLIFLOZIN IN INACTIVE LUPUS NEPHRITIS CROSS-OVER RANDOMIZED TRIAL

Abstract Background and Aims Sodium-glucose co-transporter 2 (SGLT2) inhibitors slow the progression of chronic kidney disease (CKD) with and without type 2 diabetes. Lupus nephritis (LN) patients under immunosuppression were excluded from the most important trials with SGLT2 inhibitors. Thus, efficacy and tolerance of these drugs are unknown in such patients. The present trial will assess the effect of Dapagliflozin in patients with inactive Lupus Nephritis with residual proteinuria. Method For this cross-over randomized trial, we will include adult patients with LN class III, IV (+/-V) without active nephritis but with proteinuria > 500mg/24h or UPC > 200mg/g and eGFR ≥ 20ml/min, in the maintenance treatment. RAAS inhibition should be stable for at least four weeks before the randomization. We will exclude patients with other etiologies of CKD, those with active LN lesions on the recent biopsy (AI>2), use of induction therapy in the last 12 months (Cyclophosphamide, Mycophenolate Mofetil >2 g/day and Calcineurin inhibitors) and prednisone dose ≥ 20 mg/day. Due to safety issues, we will exclude patients with recurrent urinary infections (>3 times/year). They will be randomized to receive Dapagliflozin 10mg on top of standard of care therapy or not. After 24 weeks the groups will be switched and those without Dapagliflozin will receive it for the next 24 weeks. Primary endpoint will be reduction of proteinuria compared to baseline at 6 and 12 months. Secondary endpoints will include sustained reduction of eGFR > 30%; changes in weight and blood pressure compared to baseline; and number of infections on Dapagliflozin treatment versus exclusive standard of care therapy. The sample size was calculated for 28 patients enrolled providing 80% power to detect a 25% relative risk reduction in proteinuria (α level of 0.05). Results From 85 screened class III, IV (+/- V) LN patients under maintenance therapy, we excluded 65 due to active nephritis, low proteinuria or low eGFR. Until now we included 17 patients that were randomized 1:1 to start the treatment with Dapagliflozin on top of standard care or remain with the usual therapy for 24 weeks. Patients’ baseline characteristics are described in Table 1. All patients randomized were using Mycophenolate Mofetil ≤2 g/day and RAAS inhibition and 14 of them were receiving Hydroxychloroquine. Conclusion We expect that the present trial will determine whether the SGLT2 inhibitor Dapagliflozin, added to LN maintenance therapy, could safely reduce the residual proteinuria of inactive LN patients.

Towards understanding chronic kidney disease

Chronic kidney disease (CKD) is a global health problem affecting almost 15% of the population worldwide. After renal injury, there is a nephron loss and remaining nephrons ensure the glomerular filtration rate (GFR) with compensatory hyperplasia and hypertrophy: This is called the nephron reduction. After nephron reduction, renal function will gradually decline and lead to chronic end-stage renal failure. Whatever the initial cause of the renal injury, recent data suggest there are common molecular mechanisms at the origin of CKD progression. Moreover, the renal lesions are very reproducible with glomerulosclerosis, tubular atrophy and partial epithelio-mesenchymal transition, interstitial fibrosis and vascular abnormalities. The physiopathology of CKD progression is unclear but some hypotheses have been described: i) the nephron "overwork", supported by recent works showing that the nephron reduction leads to hyperfiltration by the remaining nephrons and the stability of the GFR; ii) the "podocyte adaptation" theory, reflected by the importance of the podocytopathy in CKD progression and the crucial role of residual proteinuria in renal lesion development; iii) the activation of EGFR signaling pathways in surgical nephron reduction model and its involvement in CKD progression. Finally, CKD progression remains poorly understood and further studies will be necessary to discover new CKD molecular pathways and to develop new therapeutic insight in CKD management.

New Strategies for Volume Control in Patients with Diabetes Mellitus, a Narrative Review.

Sodium is reabsorbed all along the renal tubules. The positive impacts of sodium-glucose cotransporter-2 inhibitors (SGLT2i), angiotensin receptor neprilysin inhibitor (ARNI) and mineralocorticoid receptor antagonists (MRA) on hard renal and/or cardiac endpoints calls for the role of diuretics in nephroprotection and cardioprotection in patients with diabetes mellitus to be reviewed. Here, we review: (a) the mechanisms of action of the available natriuretics; (b) the physiological adaptations to chronic loop diuretic usage that lead to increased sodium reabsorption in the proximal and distal convoluted tubules; (c) the physiology of sodium retention in patients with diabetes mellitus; and (d) the mechanisms of aldosterone breakthrough. We show the rationale for combined diuretics to target not only the loop of Henle, but also the proximal and distal convoluted tubules. Indeed, higher residual proteinuria in patients treated with renin-angiotensin-aldosterone system (RAAS) blockers portends poorer renal and cardiovascular outcomes. Diuretics are known to optimize the reduction of proteinuria, in addition to RAAS blockers, but may favor aldosterone breakthrough in the absence of MRA. The aim of our study is to support a combined diuretics strategy to improve the management of patients with diabetes mellitus and chronic kidney disease or heart failure.

The Effect of Hydroxychloroquine on Residual Proteinuria in Patients With Immunoglobulin A Nephropathy: A Retrospective Study Based on Propensity Score Matching.

BackgroundThere is insufficient evidence to support the use of hydroxychloroquine (HCQ) in Immunoglobulin A nephropathy (IgAN) patients with high residual proteinuria in spite of 6-month supportive treatment combined with corticosteroids (P) and/or immunosuppressives (IM). This study aims to explore the effect of HCQ on residual proteinuria in IgAN.Materials and MethodsThis is a retrospective study. IgAN patients who had residual proteinuria ≥0.3 g/24 h after 6-month treatment by renin-angiotensin system inhibitors (RASI) + P ± IM were included. Groups were divided based on the different regimens and then matched by the propensity score matching method. The primary outcome was defined as the cumulative frequency of residual proteinuria reduction ≥30%.ResultsRASI (n = 183), HCQ + RASI (n = 59), RASI + P ± IM (n = 145), and HCQ + RASI + P ± IM (n = 38) groups were included. HCQ + RASI group had a higher level of residual proteinuria and a worse renal function than those in the RASI group. The renal function was worse in the HCQ + RASI + P ± IM group than that in the control group, but residual proteinuria levels were similar. After matching, there were 40 patients in the first two groups and 29 patients in the latter two groups, respectively. The cumulative frequency of residual proteinuria reduction ≥30% in HCQ + RASI + P ± IM group was higher than that in control group (86.2% vs. 62.1%, χ2 = 6.397, p = 0.011). HCQ combination treatment was one of independent factors.ConclusionThe addition of HCQ treatment can effectively reduce the residual proteinuria in IgAN patients previously treated with supportive treatment combined with P and IM treatment and the cumulative frequency of effective reduction of residual proteinuria can reach 86.2%.

Chlorthalidone and Advanced Chronic Kidney Disease.

Chlorthalidone and Advanced Chronic Kidney Disease.

Belimumab may decrease flare rate and allow glucocorticoid withdrawal in lupus nephritis (including dialysis and transplanted patient).

Belimumab (Benlysta) is currently approved for the treatment of active Lupus despite standard therapy. Few data are available on the efficacy of this drug in lupus nephritis (LN). 17 LN female followed in two Nephrology Italian Unit received belimumab for a median period of 36months (range 6-42months). The indications were: arthralgia in 3 patients, cutaneous manifestations in 2, residual proteinuria in 8, and the need to reduce steroids for severe side effects in 4. Of interest, 1 patient started therapy during Peritoneal Dialysis and continued after kidney transplantation due to non-responsive arthralgias. Arthralgia and skin manifestations resolved in all patients. Proteinuria normalized in three patients and stabilized in all but one of the others. Steroids were indefinitely stopped in six patients (35%) and reduced to around 40% of the basal dosage in the other patients. During belimumab therapy, three extrarenal and one renal SLE flares were diagnosed accounting for a rate of renal flares of 0.02/patient/year. No major adverse events leading to therapy withdrawal occurred. Arthralgia resolved, immunological parameters improved and prednisone could be reduced within few months in the patient who started belimumab during peritoneal dialysis. After kidney transplantation belimumab was stopped but due to arthralgias unresponsive to standard immunosuppressive therapy it was restarted with success. Belimumab allows the achievement of complete response together with the withdrawal or the reduction of corticosteroids in almost all our patients. Of interest its satisfactory use in a patient in peritoneal dialysis and after kidney transplantation.

Effects of Sevelamer Carbonate in Patients With CKD and Proteinuria: The ANSWER Randomized Trial

Hyperphosphatemia is associated with increased risk for chronic kidney disease (CKD) progression and reduced antiproteinuric effects of renin-angiotensin system (RAS) blockers. We investigated whether the phosphate binder sevelamer carbonate may enhance the antiproteinuric effect of RAS inhibitors in patients with CKD. Phase 2, randomized, controlled, open-label, crossover trial. Between November 2013 and December 2014, we enrolled 53 patients with CKD with estimated glomerular filtration rates (eGFRs)>15mL/min/1.73m2 and residual proteinuria with protein excretion≥0.5g/24h despite maximal tolerated ramipril and/or irbesartan therapy from 2 nephrology units in Italy. After stratification by serum phosphate level,≤4 or>4mg/dL, patients were randomly assigned to 3 months of sevelamer (1,600mg thrice daily) treatment followed by 3 months without sevelamer separated by a 1-month washout period or 3 months without sevelamer followed by 3 months with sevelamer, also separated by a 1-month washout period. The primary outcome was 24-hour proteinuria (n=49patients). Secondary outcomes included measured GFR (using iohexol plasma clearance), office blood pressure (BP), serum lipid levels, levels of inflammation and bone metabolism biomarkers, urinary electrolyte levels, and arterial stiffness. Changes in proteinuria during the 3-month treatment with (from 1.36 [IQR, 0.77-2.51] to 1.36 [IQR, 0.77-2.60] g/24h) or without (from 1.36 [IQR, 0.99-2.38] to 1.48 [IQR, 0.81-2.77] g/24h) sevelamer were similar (P=0.1). Sevelamer reduced urinary phosphate excretion without affecting serum phosphate levels. Sevelamer reduced C-reactive protein (CRP), glycated hemoglobin, and total and low-density lipoprotein cholesterol levels and increased high-density lipoprotein cholesterol levels without affecting levels of office BP, measured GFR, fibroblast growth factor 23, klotho, intact parathyroid hormone, serum vitamin D, or other urinary electrolytes. Results were similar in the low- and high-phosphate groups. Sevelamer was well tolerated. Adverse events were comparable between treatment periods. One case of transient hypophosphatemia was observed during treatment with sevelamer. Short treatment duration, lower pretreatment proteinuria than expected. 3-month sevelamer treatment did not reduce proteinuria in patients with CKD on maximal RAS blockade. Amelioration of inflammation and dyslipidemia with sevelamer treatment raises the possibility that it may confer benefit in patients with CKD beyond reduction of proteinuria. Sanofi (Milan, Italy). Registered at ClinicalTrials.gov with study number NCT01968759.

Paricalcitol versus placebo for reduction of proteinuria in kidney transplant recipients: a double-blind, randomized controlled trial.

Proteinuria after kidney transplantation is accompanied by an increased risk of graft failure. In this single-center, placebo-controlled, double-blind trial we studied whether vitamin D receptor activator paricalcitol might reduce proteinuria. Patients with urinary protein-to-creatinine ratio (UPCR) ≥20mg/mmol despite optimization of the renin angiotensin aldosterone system (RAAS) blockade were randomly assigned to receive 24weeks' treatment with 2μg/day paricalcitol or placebo. Primary endpoint was change in UPCR, and main secondary endpoints were change in urinary albumin-to-creatinine ratio (UACR) and 24-h proteinuria. Analysis was by intention to treat. One hundred and sixty-eight patients undergo randomization, and 83 were allocated to paricalcitol, and 85 to placebo. Compared with baseline, UPCR declined in the paricalcitol group (-39%, 95% CI -45 to -31) but not in the placebo group (21%, 95% CI 9 to 35), with a between group difference of -49% (95% CI -57 to -41; P<0.001). UACR and 24-h proteinuria decreased only on paricalcitol therapy and significantly differed between groups at end-of-treatment (P<0.001). Paricalcitol was well tolerated but incidence of mild hypercalcemia was higher than in placebo. In conclusion, addition of 2μg/day paricalcitol lowers residual proteinuria in kidney transplant recipients. Long-term studies are needed to determine if the reduction in proteinuria improves transplant outcomes (ClinicalTrials.gov, number NCT01436747).

Initial treatment with pulse methylprednisolone followed by short-term prednisolone and tonsillectomy for childhood IgA nephropathy.

Although a combination therapy, comprising 2-year high-dose oral prednisolone (PSL), is effective for treating childhood immunoglobulin A nephropathy (IgAN), severe adverse effects and residual proteinuria occur in some patients after the therapy. To clarify the efficacy of intravenous pulse methylprednisolone (IVMP; 15-20mg/kg; maximum 600mg/day; for 3 consecutive days/week for 3weeks) followed by short-term reduced-dose PSL (initially 1mg/kg; maximum 30mg on alternate days; tapered off within approximately 12months) and tonsillectomy as an initial treatment, we retrospectively reviewed the clinical courses of 54 consecutive children with IgAN (32 boys; mean age at onset, 12.2years; follow-up period of > 2years) after initiating the treatment. According to the Japanese pediatric IgAN guidelines, we divided the 54 patients into the following two groups: group 1, comprising 24 patients with severe IgAN, and group 2, comprising 30 patients with mild IgAN. After the treatment, proteinuria disappeared in all patients at a median of 1.6months (group 1, 2.8 months; group 2, 0.4months) and hematuria disappeared in 47 patients (87%) at a median of 13.2months (group 1, 15.9 months; group 2, 13.2months). During the follow-up period (median 5years), no severe adverse effects were observed in any patient. At the last visit, although two patients (4%) had mild proteinuria, none developed hypertension or renal insufficiency. As an initial treatment, IVMP followed by short-term PSL and tonsillectomy appears to be effective for treating childhood IgAN.

Cardiorenal prognosis by residual proteinuria level in diabetic chronic kidney disease: pooled analysis of four cohort studies.

No study has assessed whether the prognosis of coexisting diabetes mellitus and chronic kidney disease (DM-CKD) is dictated by DM per se or by the extent of proteinuria. In this pooled analysis of four prospective studies in CKD patients treated with drugs inhibiting the renin-angiotensin system, we compared the risk of all-cause mortality, fatal and non-fatal cardiovascular (CV) events and end-stage renal disease (ESRD) between patients with (n = 693) and without diabetes (n = 1481) stratified by proteinuria level (<0.15, 0.15-0.49, 0.5-1 and >1 g/day). The group with DM-CKD was older (69 ± 11 versus 65 ± 15 years), had a higher body mass index (29.6 ± 5.4 versus 27.5 ± 4.8 kg/m2) and systolic blood pressure (143 ± 19 versus 136 ± 18 mmHg), prevalent CV disease (48% versus 29%) and lower estimated glomerular filtration rate (34.5 ± 17.9 versus 36.6 ± 19.0 mL/min/1.73m2). During 4.07 years of follow-up, there were 466 patients with ESRD, 334 deaths and 401 CV events occurred. In the subgroup with urine protein <0.15 g/day (N = 662), the risks of ESRD, CV events and mortality were similar in diabetic and non-diabetic patients. Conversely, in DM-CKD patients, the mortality risk was higher in proteinuric patients {hazard ratio 1.92 [95% confidence interval (CI) 1.25-2.95); 1.99 (1.26-3.15) and 1.98 (1.28-3.06) for proteinuria 0.15-0.49, 0.5-1 and >1 g/day, respectively}, whereas in non-diabetics the mortality risk increased only for proteinuria 0.5-1 g/day [HR 1.60 (95% CI 1.07-2.40)] and >1 g/day [HR 1.69 (95% CI1.20-2.55)]. In both groups, CV risk had a trend similar to that of mortality. ESRD risk increased progressively across strata >0.5 g/day independent of diabetic status. We provide evidence that patients with non-proteinuric DM-CKD are not exposed to higher cardiorenal risk. In contrast, in the presence of moderate proteinuria and diabetes per se is associated with a higher risk of mortality and CV events, whereas the entity of abnormal proteinuria modulates ESRD risk independent of diabetes.

Endothelin A receptor antagonists in diabetic kidney disease.

Despite optimal therapy of diabetic nephropathy with agents blocking the renin-angiotensin-aldosterone system, the residual risk of nephropathy progression to end-stage renal disease (ESRD) remains high. The purpose of this review is to discuss the potential role of endothelin antagonism as a therapeutic tool to reduce residual proteinuria and delay kidney injury progression among patients with diabetic nephropathy. Preclinical studies have shown that endothelin receptor antagonists (ERAs) exert proteinuria lowering and nephroprotective actions in experimental models of diabetic nephropathy. ERAs reduce proteinuria in phase 2 trials that included therapy with renin-angiotensin-aldosterone system blockers. Safety of these agents and protection from ESRD needs to be demonstrated in phase 3 trials. Excess risk of fluid retention and heart failure risk remains. The hypothesis that the antiproteinuric effect of endothelin antagonism may be translated into a slower progression of diabetic nephropathy to ESRD is investigated in ongoing randomized trials assessing 'hard' renal endpoints. ERAs may represent a promising tool toward renoprotection in diabetic nephropathy by individualizing therapy and mitigating the risk of heart failure, if these trials are positive.

Atrasentan for the treatment of diabetic nephropathy

ABSTRACTIntroduction: Endothelin-1 (ET-1) is the most potent vasoconstrictor, and is involved in the renal regulation of salt and water homeostasis. When produced in excess in the kidney, ET-1 promotes proteinuria and tubulointerstitial injury. There is great interest in the clinical use of endothelin receptor antagonists (ERAs) in chronic kidney disease (CKD), mainly in diabetic nephropathy (DN).Areas covered: Physiopathological actions of ET-1 on the kidney. Both dual ETAR/ETBR (bosentan) or ETAR specific endothelin antagonists (avosentan and atrasentan, among others), which have progressed to early clinical development, with particular emphasis on atrasentan.Expert opinion: Different phase I and II clinical trials with ERAs in DN, mostly with atrasentan, have shown that these drugs have a marked anti-proteinuric effect on residual proteinuria when administered as add-on therapy in addition to ACEi or ARAII treatment. In the past few years, a series of randomized controlled trials investigating new approaches to DN have provided negative or inconclusive data, or even were terminated due to safety concerns or lack of efficacy. Therefore, we eagerly but cautiously await the results of the ongoing SONAR trial with atrasentan in more than 4,000 patients including assessment of renal and cardiovascular hard-end points (estimated primary completion date, July 2018).

ANCA vasculitis in a patient with Alport syndrome: a difficult diagnosis but a treatable disease!

BackgroundAlport syndrome and ANCA-associated vasculitis are both rare diseases. The co-existence of these two conditions has never been reported. There is no obvious pathogenic link between these two glomerular diseases. The management of this case highlights the importance of a systematic approach when investigating the unexpected unfavourable evolution of a known glomerulopathy.Case presentationA-17 year old caucasian boy with a genetically proven X-linked Alport syndrome presented with progressive dyspnea, fatigue and pallor. His blood tests showed a severe anemia (Hb 6.9 g/dl) with acute worsening of kidney function (serum creatinine, normal 9 months earlier, was now 3.6 mg/dl). Microscopic hematuria and proteinuria also worsened. He soon developed signs of alveolar hemorrhage. Serological tests showed the presence of perinuclear ANCA with anti MPO specificity. Kidney biopsy showed a necrotizing and crescentic glomerulonephritis. Pulses of methylprednisolone were given in combination with plasmapheresis. The patient further received 6 pulses of cyclophosphamide, followed by maintenance oral azathioprine. During the 15-months follow up he remained well with serum creatinine back to normal, and some residual proteinuria and hematuria ascribed to Alport syndrome.ConclusionWe report a young patient with the coexistence of Alport syndrome and ANCA associated vasculitis. Clinicians should be aware of the possibility of a second acquired disease in a patient with a known kidney disease, genetic in this case. This coexistence is very rare, but should be considered even if both diseases are rare, if the evolution is atypical for the single (known) primary disease. The diagnosis of the added vasculitis prompted in our case the initiation of immunosuppressive drugs, with a favourable outcome.

Dual inhibition of renin-angiotensin-aldosterone system and endothelin-1 in treatment of chronic kidney disease.

Inhibition of the renin-angiotensin-aldosterone system (RAAS) plays a pivotal role in treatment of chronic kidney diseases (CKD). However, reversal of the course of CKD or at least long-term stabilization of renal function are often difficult to achieve, and many patients still progress to end-stage renal disease. New treatments are needed to enhance protective actions of RAAS inhibitors (RAASis), such as angiotensin-converting enzyme (ACE) inhibitors (ACEIs) or angiotensin receptor blockers (ARBs), and improve prognosis in CKD patients. Inhibition of endothelin (ET) system in combination with established RAASis may represent such an approach. There are complex interactions between both systems and similarities in their renal physiological and pathophysiological actions that provide theoretical rationale for combined inhibition. This view is supported by some experimental studies in models of both diabetic and nondiabetic CKD showing that a combination of RAASis with ET receptor antagonists (ERAs) ameliorate proteinuria, renal structural changes, and molecular markers of glomerulosclerosis, renal fibrosis, or inflammation more effectively than RAASis or ERAs alone. Practically all clinical studies exploring the effects of RAASis and ERAs combination in nephroprotection have thus far applied add-on designs, in which an ERA is added to baseline treatment with ACEIs or ARBs. These studies, conducted mostly in patients with diabetic nephropathy, have shown that ERAs effectively reduce residual proteinuria in patients with baseline RAASis treatment. Long-term studies are currently being conducted to determine whether promising antiproteinuric effects of the dual blockade will be translated in long-term nephroprotection with acceptable safety profile.

Renin-angiotensin-aldosterone system blockade in chronic kidney disease: current strategies and a look ahead.

The Renin-Angiotensin-Aldosterone System (RAAS) is profoundly involved in the pathogenesis of renal and cardiovascular organ damage, and has been the preferred therapeutic target for renal protection for over 30years. Monotherapy with either an Angiotensin Converting Enzime Inhibitor (ACE-I) or an Angiotensin Receptor Blocker (ARB), together with optimal blood pressure control, remains the mainstay treatment for retarding the progression toward end-stage renal disease. Combining ACE-Is and ARBs, or either one with an Aldosterone Receptor Antagonist (ARA), has been shown to provide greater albuminuria reduction, and to possibly improve renal outcome, but at an increased risk of potentially severe side effects. Moreover, combination therapy has failed to provide additional cardiovascular protection, and large prospective trials on hard renal endpoints are lacking. Therefore this treatment should, at present, be limited to selected patients with residual proteinuria and high renal risk. Future studies with novel agents, which directly act on the RAAS at multiple levels or have a more favourable side effect profile, are greatly needed to further explore and define the potential for and the limitations of profound pharmacologic RAAS inhibition.

Moderator's view: Phosphate binders in chronic kidney disease patients: a clear ‘No’ at the moment, but stay tuned

Particularly because the risk of harm cannot be safely excluded, the use of phosphate binders in chronic kidney disease (CKD) patients demands caution. Yet, the clinical inertia concerning phosphate burden is unjustified. Inorganic, phosphate esters added to preserve food represent an important component of dietary phosphate load. These compounds are easily absorbable and have a measurable effect on serum phosphate, and therefore their use should be avoided in CKD patients. The ongoing CKD Optimal management with Binders and NicotinamidE (COMBINE) study, applying chelation by phosphate binders and intestinal Na-P channel blockade by nicotinamide, will establish whether this combination may effectively reduce serum phosphate and fibroblast growth factor 23 in pre-dialysis CKD patients and produce improvements in surrogate measures of cardiovascular and renal damages. On the other hand, the ANSWER study will ascertain whether phosphate reduction by sevelamer carbonate may have an antiproteinuric effect in CKD patients with residual proteinuria despite effective blockade of the renin-angiotensin system. At this stage of knowledge, the use of phosphate binders in pre-dialysis CKD patients cannot be recommended. Ongoing studies will tell us whether the application of these drugs may have beneficial health effects in CKD patients at the pre-dialysis stage.

Effects of pentoxifylline on proteinuria and glucose control in patients with type 2 diabetes: a prospective randomized double-blind multicenter study.

BackgroundPentoxifylline is a methylxanthine derivative with significant anti-inflammatory, anti-fibrotic, and anti-proliferative properties. Studies have shown that pentoxifylline may have renoprotective effects in patients with diabetic nephropathy. However, most of these studies were limited by small sample sizes. Therefore, we investigated whether pentoxifylline could reduce proteinuria in patients with diabetic nephropathy and residual proteinuria who received an angiotensin-converting enzyme inhibitor (ACEI) or an angiotensin II receptor blocker (ARB). We also studied the effects of pentoxifylline on glycemic control, insulin resistance, and inflammatory parameters.MethodsThis was a prospective, randomized double-blind, placebo-controlled, multi-center study. A total of 174 patients with type 2 diabetes and albuminuria (>30 mg/g of creatinine) who were taking the recommended dosage of ACEI or ARB for > 6 months and receiving conventional therapy for diabetes were randomly assigned to receive pentoxifylline (1200 mg, daily; n = 87) or a placebo (n = 87) for 6 months. The endpoints were the effects of pentoxifylline on proteinuria, renal function, glucose control, and inflammatory parameters.ResultsThe percentage changes in proteinuria from baseline in the pentoxifylline and placebo groups were a decrease of 23 % and 4 %, respectively (p = 0.012). In addition, significant reductions in fasting plasma glucose, glycated hemoglobin, and insulin resistance according to the homeostasis model assessment were observed in the pentoxifylline group compared to those in the placebo group. However there was no significant difference in serum tumor necrosis factor (TNF)-α between the groups.ConclusionsPentoxifylline therapy reduced proteinuria and improved glucose control and insulin resistance without significant change of serum TNF-α in patients with type 2 diabetic nephropathy. Therefore, pentoxifylline is a potential therapeutic alternative for treating diabetes and diabetic nephropathy.Trial registrationNCT01382303