ACE inhibitors and proteinuria

Real-world evidence of lisinopril in pediatric hypertension and nephroprotective management: a 10-year cohort study

BACKGROUND

Over the last 20 years, pediatric hypertension (pHTN) prevalence in Western society has risen from 3.5 to 9% due to childhood overweight, obesity, and secondary kidney and cardiological conditions. Few studies have assessed commonly used antihypertensive medication lisinopril's (ACE-inhibitor) long-term efficacy and the long-term value of renin-angiotensin-aldosterone system (RAAS) biomarkers.

METHODS

This is a retrospective cohort study at Ghent University Hospital, Belgium, with 106 young patients (1-18 years) treated with lisinopril due to hypertension (HTN) and chronic kidney disease (CKD) assessed for treatment outcomes against clinical benchmarks over 10 years.

RESULTS

Lisinopril was mainly initiated for secondary hypertension or nephroprotection (89%) due to kidney causes. A starting dose across groups was lower than 0.07 mg/kg for 48% (n = 50). HTN patients without CKD achieved systolic blood pressure below the 95th percentile within 2 years, but efficacy declined after 2.5 years. CKD patients maintained a steady response, reaching systolic targets by 40 months and showing improved diastolic control over 70 months. Proteinuria reduction had a median urine protein creatinine ratio (UPCR) to 0.57 g/g at 6 months, with a reappearance of UPCR 2 g/g creatinine after 40 months. Aldosterone breakthrough occurred from 6 months onward in all groups. Over 70 months, aldosterone and aldosterone-renin-ratio (ARR) progression significantly differ between children with and without normal kidney function.

CONCLUSIONS

Treatment efficacy for systolic blood pressure in hypertensive patients with abnormal kidney function diminishes after 2.5 years and for proteinuria in children after 3 years, highlighting the need for dosage recalibration according to guidelines and/or the need for alternative treatments.

Molecular Targets of Novel Therapeutics for Diabetic Kidney Disease: A New Era of Nephroprotection

Diabetic kidney disease (DKD) is a chronic microvascular complication in patients with diabetes mellitus (DM) and the leading cause of end-stage kidney disease (ESKD). Although glomerulosclerosis, tubular injury and interstitial fibrosis are typical damages of DKD, the interplay of different processes (metabolic factors, oxidative stress, inflammatory pathway, fibrotic signaling, and hemodynamic mechanisms) appears to drive the onset and progression of DKD. A growing understanding of the pathogenetic mechanisms, and the development of new therapeutics, is opening the way for a new era of nephroprotection based on precision-medicine approaches. This review summarizes the therapeutic options linked to specific molecular mechanisms of DKD, including renin-angiotensin-aldosterone system blockers, SGLT2 inhibitors, mineralocorticoid receptor antagonists, glucagon-like peptide-1 receptor agonists, endothelin receptor antagonists, and aldosterone synthase inhibitors. In a new era of nephroprotection, these drugs, as pillars of personalized medicine, can improve renal outcomes and enhance the quality of life for individuals with DKD.

Using Renin Activity to Guide Mineralocorticoid Receptor Antagonist Therapy in Patients with Low Renin and Hypertension

BACKGROUND

Mineralocorticoid receptor antagonists (MRAs) are often empirically used for patients with low-renin hypertension (LRH) or probable primary aldosteronism (PA) who decline surgery. However, the optimal approach to MRA therapy is unknown. Studies have shown that a rise in renin is an effective biomarker of prevention of cardiovascular complications of PA. This study aimed to determine whether empiric MRA therapy in patients with LRH or probable PA targeting unsuppressed renin is associated with a decrease in blood pressure and/or proteinuria.

METHODS

Retrospective single-center cohort study from 2005 to 2021 included adults with LRH or probable PA (renin activity <1.0 ng/ml/h and detectable aldosterone levels). All patients were empirically treated with an MRA, targeting renin ≥1.0 ng/ml/h.

RESULTS

Out of 39 patients studied, 32 (82.1%) achieved unsuppressed renin. Systolic and diastolic blood pressure decreased from 148.0 and 81.2 to 125.8 and 71.6 mm Hg, respectively (P < 0.001 for both). Similar blood pressure reductions were seen whether patients had high (>10 ng/dl) or low (<10 ng/dl) aldosterone levels. The majority (24/39; 61.5%) of patients had at least one baseline anti-hypertensive medication stopped. Among the six patients who had detectable proteinuria and albumin-to-creatinine (ACR) measurements post-treatment, the mean ACR decreased from 179.0 to 36.1 mg/g (P = 0.03). None of the patients studied had to completely stop treatment due to adverse reactions.

CONCLUSIONS

Empiric MRA therapy in patients with LRH or probable PA targeting unsuppressed renin can safely and effectively improve blood pressure control and reduce proteinuria.

Exploring the Impact of ACE Inhibition in Immunity and Disease

Angiotensin-converting enzyme (ACE) is a zinc-dependent dipeptidyl carboxypeptidase and is crucial in the renin-angiotensin-aldosterone system (RAAS) but also implicated in immune regulation. Intrinsic ACE has been detected in several immune cell populations, including macrophages and neutrophils, where its overexpression results in enhanced bactericidal and antitumour responses, independent of angiotensin II. With roles in antigen presentation and inflammation, the impact of ACE inhibitors must be explored to understand how ACE inhibition may impact our ability to clear infections or malignancy, particularly in the wake of the coronavirus (SARS-CoV2) pandemic and as antibiotic resistance grows. Patients using ACE inhibitors may be more at risk of postsurgical complications as ACE inhibition in human neutrophils results in decreased ROS and phagocytosis whilst angiotensin receptor blockers (ARBs) have no effect. In contrast, ACE is also elevated in certain autoimmune diseases such as rheumatoid arthritis and lupus, and its inhibition benefits patient outcome where inflammatory immune cells are overactive. Although the ACE autoimmune landscape is changing, some studies have conflicting results and require further input. This review seeks to highlight the need for further research covering ACE inhibitor therapeutics and their potential role in improving autoimmune conditions, cancer, or how they may contribute to immunocompromise during infection and neurodegenerative diseases. Understanding ACE inhibition in immune cells is a developing field that will alter how ACE inhibitors are designed in future and aid in developing therapeutic interventions.

Barker Hypothesis and Hypertension

Early onset hypertension is one of many major medical disorders that have evolved over the current millennium across both the developing as well as the developed world. Though various mechanisms have been postulated for the evolution of hypertension in these individuals, one of the most relevant ones is that of low birth weight and its association with hypertension. Barker from historical evidence has postulated the foetal onset adult disease (FOAD) or Thrifty phenotype on Low Birth Weight (LBW) associated hypertension. Later, Brenner highlighted the importance of low nephron mass and future implications. In this review we elaborate the mechanisms that were postulated for LBW-related hypertension as well the potential antihypertensive therapy that may be used in these individuals.

Diffuse membranoproliferative glomerulonephritis with focal sclerosis and renal amyloidosis in an adult male with autosomal dominant dystrophic epidermolysis bullosa: a case report

Previous reports of glomerular disease in adult patients with autosomal dominant dystrophic epidermolysis bullosa (EB) are limited and include post-infectious glomerulonephritis, IgA nephropathy, amyloidosis, and leukocytoclastic vasculitis. To our knowledge, membranoproliferative glomerulonephritis (MPGN) has not been described before. We report a case of a 39-year-old male with autosomal dominant dystrophic EB, presenting with bilateral leg swelling of one-week duration. There was no other significant past medical history. The physical examination was remarkable for scars and erosions over all body areas, with all extremities with blisters and ulcers covered, absent finger and toenails and bilateral lower extremity edema. Serum creatinine was 0.9 mg/dL, albumin 1.3 g/dL and urine protein excretion 3.7 g/24 h. Viral markers (hepatitis-B, C, and HIV), complement c3 and c4 levels and auto-immune antibody profile all remained negative or within normal limits. Renal ultrasound and echocardiogram were normal. Renal biopsy recovered 14 glomeruli, all with proliferation of mesangial and endothelial cells as well as an expansion of the mesangial matrix, focal segmental sclerosis and amorphous homogeneous deposits demonstrating apple-green birefringence under polarized light with Congo red stain. Our observation emphasizes the importance of recognizing MPGN and secondary amyloidosis in patients with EB, especially with the availability of newer treatment modalities.

How Do Kidneys Adapt to a Deficit or Loss in Nephron Number?

A deficit or loss in the number of nephrons, the functional unit of the kidney, can induce compensatory growth and hyperfunction of remaining nephrons. An increase in single nephron glomerular filtration rate (SNGFR) aims to compensate but may be deleterious in the long term. The increase in SNGFR is determined by the dynamics of nephron loss, total remaining GFR, the body's excretory demand, and the functional capacity to sustain single nephron hyperfunction.

Chronic Lyme borreliosis associated with minimal change glomerular disease: a case report

BACKGROUND

There are only few cases of renal pathology induced by Lyme borreliosis in the literature, as this damage is rare and uncommon in humans. This patient is the first case of minimal change glomerular disease associated with chronic Lyme borreliosis.

CASE PRESENTATION

A 65-year-old Caucasian woman was admitted for an acute edematous syndrome related to a nephrotic syndrome. Clinical examination revealed violaceous skin lesions of the right calf and the gluteal region that occurred 2 years ago. Serological tests were positive for Lyme borreliosis and skin biopsy revealed lesions of chronic atrophic acrodermatitis. Renal biopsy showed minimal change glomerular disease. The skin lesions and the nephrotic syndrome resolved with a sequential treatment with first ceftriaxone and then corticosteroids.

CONCLUSION

We report here the first case of minimal change disease associated with Lyme borreliosis. The pathogenesis of minimal change disease in the setting of Lyme disease is discussed but the association of Lyme and minimal change disease may imply a synergistic effect of phenotypic and bacterial factors. Regression of proteinuria after a sequential treatment with ceftriaxone and corticosteroids seems to strengthen this conceivable association.

Blood pressure goals and treatment in pregnant patients with chronic kidney disease

As the age of pregnant women and prevalence of obesity and diabetes are increasing, so is the prevalence of medical disorders during pregnancy, particularly hypertension and the associated CKD. Pregnancy can worsen kidney function in women with severe disease, and hypertension puts them at risk for pre-eclampsia and the associated complications. There are no specific guidelines for hypertension management in this population, and tight control will not prevent pre-eclampsia. Women with end-stage kidney disease should be placed on intense dialysis regimens to improve obstetric outcomes, and angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are best avoided. This article will review the rationale for a management plan that includes a multidisciplinary team to discuss risks and develop a plan before conception, antepartum monitoring for maternal and fetal morbidity, individualization of medical management using medications with established records during pregnancy, and balancing the level of blood pressure control proved to protect kidney function against the potential effects that aggressive blood pressure control could have on the fetal-placental unit.

Proteinuria in special populations: pregnant women and children

Proteinuria is the hallmark of glomerular kidney disease. It is used diagnostically to follow disease progression and to determine response to therapy. Thus, it is necessary to have an understanding of the mechanisms of proteinuria and the limitations to its accurate assessment in special populations. In this article, we review 2 special populations--pregnant women and children--providing insight into their unique circumstances that require consideration when assessing proteinuria.

Detection of autosomal dominant polycystic kidney disease by NMR spectroscopic fingerprinting of urine

Autosomal dominant polycystic kidney disease (ADPKD) is a frequent cause of kidney failure; however, urinary biomarkers for the disease are lacking. In a step towards identifying such markers, we used multidimensional-multinuclear nuclear magnetic resonance (NMR) spectroscopy with support vector machine-based classification and analyzed urine specimens of 54 patients with ADPKD and slightly reduced estimated glomerular filtration rates. Within this cohort, 35 received medication for arterial hypertension and 19 did not. The results were compared with NMR profiles of 46 healthy volunteers, 10 ADPKD patients on hemodialysis with residual renal function, 16 kidney transplant patients, and 52 type 2 diabetic patients with chronic kidney disease. Based on the average of 51 out of 701 NMR features, we could reliably discriminate ADPKD patients with moderately advanced disease from ADPKD patients with end-stage renal disease, patients with chronic kidney disease of other etiologies, and healthy probands with an accuracy of >80%. Of the 35 patients with ADPKD receiving medication for hypertension, most showed increased excretion of proteins and also methanol. In contrast, elevated urinary methanol was not found in any of the control and other patient groups. Thus, we found that NMR fingerprinting of urine differentiates ADPKD from several other kidney diseases and individuals with normal kidney function. The diagnostic and prognostic potential of these profiles requires further evaluation.

Early renal abnormalities in autosomal dominant polycystic kidney disease

BACKGROUND AND OBJECTIVES

Potential therapeutic interventions are being developed for autosomal dominant polycystic kidney disease (ADPKD). A pivotal question will be when to initiate such treatment, and monitoring disease progression will thus become more important. Therefore, the prevalence of renal abnormalities in ADPKD at different ages was evaluated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Included were 103 prevalent ADPKD patients (Ravine criteria). Measured were mean arterial pressure (MAP), total renal volume (TRV), GFR, effective renal plasma flow (ERPF), renal vascular resistance (RVR), and filtration fraction (FF). Twenty-four-hour urine was collected. ADPKD patients were compared with age- and gender-matched healthy controls.

RESULTS

Patients and controls were subdivided into quartiles of age (median ages 28, 37, 42, and 52 years). Patients in the first quartile of age had almost the same GFR when compared with controls, but already a markedly decreased ERPF and an increased FF (GFR 117 +/- 32 versus 129 +/- 17 ml/min, ERPF 374 +/- 119 versus 527 +/- 83 ml/min, FF 32% +/- 4% versus 25% +/- 2%, and RVR 12 (10 to 16) versus 8 (7 to 8) dynes/cm(2), respectively). Young adult ADPKD patients also had higher 24-hour urinary volumes, lower 24-hour urinary osmolarity, and higher urinary albumin excretion (UAE) than healthy controls, although TRV in these young adult patients was modestly enlarged (median 1.0 L).

CONCLUSIONS

Already at young adult age, ADPKD patients have marked renal abnormalities, including a decreased ERPF and increased FF and UAE, despite modestly enlarged TRV and near-normal GFR. ERPF, FF, and UAE may thus be better markers for disease severity than GFR.

Can we slow the progression of chronic kidney disease?

PURPOSE OF REVIEW

Childhood chronic kidney disease usually progresses towards end-stage renal failure once a critical impairment of renal function has occurred. This process is largely independent of the underlying renal disease. Recent clinical trials have provided evidence that the progressive course of chronic kidney disease can be slowed substantially by pharmacological intervention.

RECENT FINDINGS

Hypertension and proteinuria are the most important independent risk factors for renal disease progression in both adult and pediatric nephropathies. Pharmacological blockade of the renin-angiotensin system provides efficient control of blood pressure and proteinuria, and superior long-term renoprotection compared with other antihypertensive agents. Recent pediatric evidence supports the renoprotective efficacy of tight blood pressure control aiming for the low-normal range. In addition, promising preliminary findings suggest an additional renoprotective potential by correction of metabolic acidosis and hyperuricemia and by administration of antiproliferative and antioxidative drugs.

SUMMARY

Pharmacological renoprotection currently focuses on antihypertensive and antiproteinuric treatment by blockade of the renin-angiotensin system. Intensified blood pressure control can improve 5-year renal survival by 35% in children with chronic kidney disease. Additional complementary strategies under current clinical evaluation bear potential to improve renal survival even further.

Strict blood-pressure control and progression of renal failure in children

BACKGROUND

Although inhibition of the renin-angiotensin system delays the progression of renal failure in adults with chronic kidney disease, the blood-pressure target for optimal renal protection is controversial. We assessed the long-term renoprotective effect of intensified blood-pressure control among children who were receiving a fixed high dose of an angiotensin-converting-enzyme (ACE) inhibitor.

METHODS

After a 6-month run-in period, 385 children, 3 to 18 years of age, with chronic kidney disease (glomerular filtration rate of 15 to 80 ml per minute per 1.73 m(2) of body-surface area) received ramipril at a dose of 6 mg per square meter of body-surface area per day. Patients were randomly assigned to intensified blood-pressure control (with a target 24-hour mean arterial pressure below the 50th percentile) or conventional blood-pressure control (mean arterial pressure in the 50th to 95th percentile), achieved by the addition of antihypertensive therapy that does not target the renin-angiotensin system; patients were followed for 5 years. The primary end point was the time to a decline of 50% in the glomerular filtration rate or progression to end-stage renal disease. Secondary end points included changes in blood pressure, glomerular filtration rate, and urinary protein excretion.

RESULTS

A total of 29.9% of the patients in the group that received intensified blood-pressure control reached the primary end point, as assessed by means of a Kaplan-Meier analysis, as compared with 41.7% in the group that received conventional blood-pressure control (hazard ratio, 0.65; confidence interval, 0.44 to 0.94; P=0.02). The two groups did not differ significantly with respect to the type or incidence of adverse events or the cumulative rates of withdrawal from the study (28.0% vs. 26.5%). Proteinuria gradually rebounded during ongoing ACE inhibition after an initial 50% decrease, despite persistently good blood-pressure control. Achievement of blood-pressure targets and a decrease in proteinuria were significant independent predictors of delayed progression of renal disease.

CONCLUSIONS

Intensified blood-pressure control, with target 24-hour blood-pressure levels in the low range of normal, confers a substantial benefit with respect to renal function among children with chronic kidney disease. Reappearance of proteinuria after initial successful pharmacologic blood-pressure control is common among children who are receiving long-term ACE inhibition. (ClinicalTrials.gov number, NCT00221845.)

What predicts progression and regression of urinary albumin excretion in the nondiabetic population?

An increase or decrease in urinary albumin excretion (UAE) is associated with, respectively, a higher or lower risk for renal and cardiovascular disease, independent of widely known cardiovascular risk factors. This study aimed to identify factors that are associated with changes in UAE in the nondiabetic population using data of the Prevention of Renal and Vascular End stage Disease (PREVEND) Study, a community-based prospective cohort study. Data of the 6647 nondiabetic participants who completed the first (1997 through 2001) and second (2001 through 2003) screening were used. Change in UAE was categorized as regression (n = 650), stable (n = 5240), or progression (n = 757) on the basis of change in class during follow-up, with classes being a UAE <15, 15 to 30, 30 to 300, and >300 mg/24 h. With the use of stepwise forward multinomial regression analysis changes in BP, fasting glucose concentration, and start of antihypertensive drugs were found to be the most important modifiable variables associated with the risk for progression and regression (P < 0.01 for likelihood ratio test). The odds ratios to develop regression or progression of UAE during follow-up were 0.64 (95% confidence interval [CI] 0.57 to 0.73) and 1.91 (95% CI 1.72 to 2.12), respectively, per 10-mmHg increase in BP during follow-up, 0.89 (95% CI 0.80 to 0.98) and 1.09 (95% CI 1.01 to 1.17), respectively, per 1-mmol/L increase of fasting glucose levels during follow-up, and 1.57 (95% CI 1.21 to 2.06) and 0.70 (95% CI 0.51 to 0.95), respectively, for start of antihypertensive drugs during follow-up. These associations were independent of baseline BP, glucose, body mass index, estimated GFR, and UAE and changes in high-sensitivity C-reactive protein during follow-up. In conclusion, changes in glucose concentration and BP and start of antihypertensive drugs (angiotensin-converting enzyme inhibitors/angiotensin receptor blockers in >50% of cases) are associated with progression and regression of UAE in the nondiabetic population. Although associations do not necessarily suggest causality, it is hypothesized that in the general population, the most important ways to reduce UAE are by lowering glucose concentration and BP (including start of antihypertensive medication), even in normotensive, nondiabetic individuals.

The importance of blood pressure control in the patient with diabetes

In individuals with diabetes mellitus, higher risk for renal and cardiovascular disease is seen with blood pressure levels >130/80 mm Hg. Findings of several studies, as well as new guidelines, indicate that individuals with diabetes will benefit from more aggressive treatment of hypertension. Angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, diuretics, beta-adrenoceptor blockers, and calcium-channel blockers are effective antihypertensive agents in type 2 diabetes. Moreover, combinations of these agents are frequently required to reach the target blood pressure of <130/80 mm Hg and reduce risk for renal and cardiovascular events. All of these agents have demonstrated benefits in treating patients. Clinical evidence also indicates that the new vasodilating beta-blockers offer advantages beyond blood pressure control, including cardiovascular risk reduction without exacerbating metabolic parameters. With increased awareness of the need for aggressive treatment of hypertension, clinicians can provide significant benefit to their patients with diabetes. The new beta-blockers may play an important role in achieving blood pressure goals.