Prescribing angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in chronic kidney disease (Review Article)

Global forecasting of chronic kidney disease mortality rates and numbers with the generalized additive model

BACKGROUND

Chronic kidney disease (CKD) is an important public health problem worldwide; therefore, forecasting CKD mortality rates and death numbers globally is vital for planning CKD prevention programs. This study aimed to characterize the temporal trends in CKD mortality at the international level from 1990 to 2019 and predict CKD mortality rates and numbers until 2030.

METHODS

Data were obtained from the Global Burden of Disease 2019 Study. A joinpoint regression model was used to estimate the average annual percentage change in CKD mortality rates and numbers. Finally, we used a generalized additive model to predict CKD mortality through 2030.

RESULTS

The number of CKD-related deaths worldwide increased from 591.80 thousand in 1990 to 1425.67 thousand in 2019. The CKD age-adjusted mortality rate increased from 15.95 per 100,000 people to 18.35 per 100,000 people during the same period. Between 2020 and 2030, the number of CKD deaths is forecasted to increase further to 1812.85 thousand by 2030. The CKD age-adjusted mortality rate is expected to decrease slightly to 17.76 per 100,000 people (95% credible interval (CrI): 13.84 to 21.68). Globally, it is predicted that in the next decade, the CKD mortality rate will decrease in men, women, all subgroups of disease etiology except glomerulonephritis, people younger than 40 years old, and all groupings of countries based on the sociodemographic index (SDI) except high-middle-SDI countries.

CONCLUSIONS

The CKD mortality rate is predicted to decrease in the next decade. However, more attention should be given to people with glomerulonephritis, people over 40 years old, and people in high- to middle-income countries because the mortality rate due to CKD in these subgroups is expected to increase until 2030.

Ginsenoside Rg3 Attenuates Angiotensin II-Mediated Renal Injury in Rats and Mice by Upregulating Angiotensin-Converting Enzyme 2 in the Renal Tissue

Angiotensin II- (Ang II-) mediated renal injury represents a major pathogenetic mechanism in most chronic kidney diseases. Our previous research demonstrated that ginsenoside Rg3 (Rg3) attenuates Ang II elevation in the myocardium in spontaneously hypertensive rats (SHR). It is possible that Rg3 has similar effects in the renal tissue. In this research, we first demonstrated that Rg3 could attenuate Ang II increase in the kidney of SHR and reduce hypertensive nephropathy progression. Then, we found that Rg3 attenuated Ang II increase by upregulating angiotensin-converting enzyme 2 (ACE2) in the renal tissue. We confirmed this finding in an exogenous Ang II-infused mice model of renal injury, and two models showed consistent results. In conclusion, Rg3 attenuates Ang II-mediated renal injury in rats and mice by upregulating ACE2 in the renal tissue. This research is the first to demonstrate that Rg3 increases tissue ACE2 levels in vivo.

A patent herbal drug Yi-Shen-Hua-Shi granule ameliorates C-BSA-induced chronic glomerulonephritis and inhabits TGFβ signaling in rats

ETHNOPHARMACOLOGY RELEVANCE

Yi-Shen-Hua-Shi (YSHS) granule is a modern Chinese patent drug for treating chronic glomerulonephritis (CGN). It is derived from a traditional Chinese medicine formula Sheng-Yang-Yi-Wei decoction that is used to treat CGN in ancient China. Pharmacological activities of YSHS granule have not been reported. In this work, we investigated the anti-CGN effects and TGFβ signaling-related mechanism of action of this herbal drug.

MATERIALS AND METHODS

The rat model of CGN was established by injection of cationization-bovine serum albumin (C-BSA) for five weeks. After finishing C-BSA injection, drugs were intragastrically administered to the rats once daily for four weeks. Clinical signs were recorded daily. Serum and urine biochemical parameters were analyzed by respective kits. Protein levels were examined by Western blotting. Pathological changes of renal tissues were evaluated by HE and Masson's trichrome staining.

RESULTS AND CONCLUSIONS

No significant differences in clinical signs and body weights were found among normal, model and drug treatment groups. Proteinuria; albuminuria; increased urine volume; elevated urea nitrogen, creatinine, total cholesterol and triglyceride levels in sera; decreased serum total protein and albumin; as well as renal pathological damage and fibrosis were observed in CGN model rats. YSHS granule ameliorated all the abnormal behavioral and biochemical changes in the model rats. Mechanical investigations showed that YSHS granule down-regulated proteins levels of TGFβ1, phospho-Smad2/3 (Thr 8) and Smad4 in rat renal tissues. In conclusion, YSHS granule demonstrates therapeutic effects in a rat model of CGN, and inhibition of the TGFβ/Smad signaling pathway is involved in the mechanism of action of the granule. This study provides a pharmacological basis for the use of modern YSHS granule and ancient Sheng-Yang-Yi-Wei decoction in treating CGN.

AT1 Receptor Antagonism Improves Structural, Functional, and Biomechanical Properties in Resistance Arteries in a Rodent Chronic Kidney Disease Model

BACKGROUND

The renin-angiotensin system, in particular Angiotensin II (AngII), plays a significant role in the pathogenesis of hypertension in chronic kidney disease (CKD). Effects of chronic AT1 receptor antagonism were investigated in a genetic hypertensive rat model of CKD, the Lewis polycystic kidney (LPK) rat.

METHODS

Mixed-sex LPK and Lewis control rats (total n = 31) were split between treated (valsartan 60 mg/kg/day p.o. from 4 to 18 weeks) and vehicle groups. Animals were assessed for systolic blood pressure and urine biochemistry, and after euthanasia, blood collected for urea and creatinine analysis, confirming the hypertensive and renal phenotype. Mesenteric resistance vasculature was assessed using pressure myography and histology.

RESULTS

Valsartan treatment improved vascular structure in LPK rats, increasing internal and external diameter values and reducing wall thickness (untreated vs. treated LPK: 53.19 ± 3.29 vs. 33.93 ± 2.17 μm) and wall-lumen ratios (untreated vs. treated LPK: 0.52 ± 0.09 vs. 0.16 ± 0.01, all P < 0.0001). Endothelium dysfunction, as measured by maximal response to acetylcholine (Rmax), was normalized with treatment (untreated vs. treated LPK: 69.56 ± 4.34 vs. 103.05 ± 4.13, P < 0.05), increasing the relative contributions of nitric oxide and endothelium-derived hyperpolarization to vasorelaxation while downregulating the prostanoid contribution. Biomechanical properties also improved with treatment, as indicated by an increase in compliance, decrease in intrinsic stiffness and alterations in the artery wall composition, which included decreases in collagen density and collagen/elastin ratio.

CONCLUSIONS

Our results highlight the importance of AngII as a driver of resistance vessel structural, functional, and biomechanical dysfunction and provide insight as to how AT1 receptor blockade exerts therapeutic efficacy in CKD.

Chronic kidney disease in low-income to middle-income countries: the case for increased screening

Chronic kidney disease (CKD) is fast becoming a major public health issue, disproportionately burdening low-income to middle-income countries, where detection rates remain low. We critically assessed the extant literature on CKD screening in low-income to middle-income countries. We performed a PubMed search, up to September 2016, for studies on CKD screening in low-income to middle-income countries. Relevant studies were summarised through key questions derived from the Wilson and Jungner criteria. We found that low-income to middle-income countries are ill-equipped to deal with the devastating consequences of CKD, particularly the late stages of the disease. There are acceptable and relatively simple tools that can aid CKD screening in these countries. Screening should primarily include high-risk individuals (those with hypertension, type 2 diabetes, HIV infection or aged >60 years), but also extend to those with suboptimal levels of risk (eg, prediabetes and prehypertension). Since screening for hypertension, type 2 diabetes and HIV infection is already included in clinical practice guidelines in resource-poor settings, it is conceivable to couple this with simple CKD screening tests. Effective implementation of CKD screening remains a challenge, and the cost-effectiveness of such an undertaking largely remains to be explored. In conclusion, for many compelling reasons, screening for CKD should be a policy priority in low-income to middle-income countries, as early intervention is likely to be effective in reducing the high burden of morbidity and mortality from CKD. This will help health systems to achieve cost-effective prevention.

Midkine in nephrogenesis, hypertension and kidney diseases

Midkine (MK; K; gene abbreviation, Mdk: mus musculus, MDK: homo sapiens) is a multifunctional heparin-binding growth factor that regulates cell growth, survival and migration as well as anti-apoptotic activity in nephrogenesis and development. Proximal tubular epithelial cells are the main sites of MK expression in the kidneys. The pathophysiological roles of MK are diverse, ranging from the development of acute kidney injury (AKI) to the progression of chronic kidney disease, often accompanied by hypertension, renal ischaemia and diabetic nephropathy. The obvious hypertension that develops in Mdk(+/+) mouse models of renal ablation compared with Mdk(-/-) mice eventually leads to progressive renal failure, such as glomerular sclerosis and tubulointerstitial damage associated with elevated plasma angiotensin (Ang) II levels. MK is also induced in the lung endothelium by oxidative stress and subsequently up-regulated by ACE, which hydrolyzes Ang II to induce further oxidative stress, thus accelerating MK generation; this leads to a vicious cycle of positive feedback in the MK-Ang II pathway. Kidney-lung interactions involving positive feedback between the renin-angiotensin system and MK might partly account for the pathogenesis of hypertension and kidney damage. MK is also involved in the pathogenesis of AKI and diabetic nephropathy through the recruitment of inflammatory cells. In contrast, MK plays a protective role against crescentic glomerulonephritis, by down-regulating plasminogen activator inhibitor-1. These diverse actions of MK might open up new avenues for targeted approaches to treating hypertension and various renal diseases.

LINKED ARTICLES

This article is part of a themed section on Midkine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-4.

Implementation of a clinical practice guideline for identification of microalbuminuria in the pediatric patient with type 1 diabetes

Evidence-based practice is a shift in the health care culture from basing decisions on consensus opinion, past practice, and precedent toward the use of rigorous analysis of scientific evidence using outcomes research and clinical evidence to guide clinical decision making. The development of evidence-based clinical practice guidelines (CPG) is critical to guide the assessment and management of children with diabetes. This article provides an overview of the infrastructure and processes that are crucial to providing evidence-based care in a large urban pediatric diabetes center. Development of a CPG to identify microalbuminuria in children with type 1 diabetes is discussed.

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.

Combination therapy with an angiotensin-converting-enzyme inhibitor and an angiotensin II receptor antagonist ameliorates microinflammation and oxidative stress in patients with diabetic nephropathy

Aims/Introduction

Recent studies have pointed to the effectiveness of combination therapy with an angiotensin‐converting‐enzyme inhibitor (ACEI) and an angiotensin receptor blocker (ARB) for diabetic nephropathy. However, some controversy over this combination treatment remains and the mechanisms underlying its renoprotective effects have not been fully clarified. Therefore, we compared the renoprotective effects of imidapril (ACEI) and losartan (ARB) combination therapy with losartan monotherapy in patients with diabetic nephropathy. We also compared the anti‐inflammatory and anti‐oxidative stress effects of these two treatments.

Materials and Methods

A total of 32 Japanese patients with type 2 diabetes and nephropathy were enrolled. Patients were randomized to either 100 mg/day losartan (n = 16) or 50 mg/day losartan plus 5 mg/day imidapril (n = 16). We evaluated clinical parameters, serum concentrations of high‐sensitivity C‐reactive protein (hs‐CRP), soluble intercellular adhesion molecule‐1 (sICAM‐1), interleukin‐18 (IL‐18) and monocyte chemotactic protein‐1 (MCP‐1), and the urinary concentrations of IL‐18, MCP‐1 and 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) at 24 and 48 weeks after starting treatment.

Results

Blood pressure was not significantly different between the two groups. The serum levels of hs‐CRP, sICAM‐1 and IL‐18, as well as urinary excretion of albumin, IL‐18 and 8‐OHdG decreased significantly in the combination therapy group at 48 weeks. The percent decreases in serum IL‐18 concentrations and urinary IL‐18 and 8‐OHdG were significantly greater in the combination therapy group than in the monotherapy group.

Conclusions

Combination therapy with an ACEI and an ARB could be beneficial for treating diabetic nephropathy through its anti‐inflammatory and anti‐oxidative stress effects.

Angiotensin-converting enzyme inhibitor limits pulse-wave velocity and aortic calcification in a rat model of cystic renal disease

The effect of angiotensin-converting enzyme inhibition on function and structure of the aorta was studied in the Lewis polycystic kidney (LPK) rat model of cystic renal disease and Lewis controls. Pulse-wave velocity (PWV) was recorded under urethane anesthesia (1.3 g/kg ip) in mixed-sex animals aged 6 and 12 wk and in 12-wk-old animals treated with perindopril (3 mg·kg(-1)·day(-1) po) from age 6-12 wk. Tail-cuff systolic pressures were recorded over the treatment period. After PWV measurements, animals were euthanized and the aorta was removed for histomorphological and calcium analysis. Hypertension in LPK at 6 and 12 wk was associated with a shift of the PWV curve upward and to the right, indicating a decrease in aortic compliance, which was significantly reduced by perindopril. LPK demonstrated greater aortic calcification (6 wk: 123 ± 19 vs. 65 ± 7 and 12 wk: 406 ± 6 vs. 67 ± 6 μmol/g, P < 0.001, LPK vs. Lewis, respectively). This was reduced by treatment with perindopril (172 ± 48 μmol/g, 12 wk LPK P < 0.001). Medial cross-sectional area and elastic modulus/wall stress of the aorta were greater in LPK vs. Lewis control animals at 6 and 12 wk of age and showed an age-related increase that was prevented by treatment with perindopril (P < 0.001). Perindopril also ameliorated the degradation of elastin, increase in collagen content, and medial elastocalcinosis seen in 12-wk LPK. Overall, perindopril improved the structural and functional indices of aortic stiffness in the LPK rats, demonstrating a capacity for angiotensin-converting enzyme inhibition to limit vascular remodeling in chronic kidney disease.

Angiotensin II, a missing node in new pathogenic glomerulotubular feedback loop

Recently, a pathogenic glomerulotubular feedback loop was proposed to be a mechanism involving in the transition from acute kidney diseases to chronic status, with highlighting immune cells as a center of this loop. Several important limitations largely reduce its applicable content. Here we amended this proposal by introducing Ang II as a missing node into the paradigm. We believe that better understanding key questions such as interactions between Ang II and immune cells may foster new promising therapeutic options in the prevention of acute-to-chronic transition.

Hypertension in small animal kidney disease

Kidney disease is commonly associated with hypertension in dogs, cats and other species. There are multiple mechanisms underlying the development of renal hypertension including sodium retention, activation of the renin-angiotensin system and sympathetic nerve stimulation. The relative importance of these and other mechanisms may vary both between species and according to the type of kidney disease that is present. Consideration of underlying disease mechanisms may aid in the rational choice of therapy in hypertensive patients.

Prevention of myocardial fibrosis by N-acetyl-seryl-aspartyl-lysyl-proline in diabetic rats

Ac-SDKP (N-acetyl-seryl-aspartyl-lysyl-proline) is a physiological tetrapeptide hydrolysed by ACE (angiotensin-converting enzyme). In experimental models of hypertension, Ac-SDKP has antifibrotic effects in the heart; however, the role of Ac-SDKP in diabetic cardiomyopathy is currently unknown. The aim of the present study was to evaluate the effect of Ac-SDKP on cardiac systolic and diastolic function, and interstitial and perivascular fibrosis in the heart of diabetic rats.Diabetes was induced in 55 Sprague-Dawley rats by streptozotocin injection. Control rats (n=18)underwent only buffer injection.Out of the 55 diabetic rats, 19 were chronically treated with insulin and 13 with the ACEI (ACE inhibitor) ramipril (3 mg x kg(-1 )of body weight x day(-1)). At 2 months after the onset of diabetes, Ac-SDKP (1 mg x kg(-1) of body weight x day(-1)) was administered by osmotic minipumps for 8 weeks to eight control rats, 13 diabetic rats, seven diabetic rats treated with ramipril and nine insulin-treated diabetic rats. Diabetic rats had a significant increase in blood glucose levels. Left ventricular interstitial and perivascular fibrosis, and TGF-beta1 (transforming growth factor-beta1) protein levels were increased in diabetic rats, but not in insulin-treated diabetic rats and ramipril-treated diabetic rats, compared with control rats. Ac-SDKP administration significantly reduced left ventricular interstitial and perivascular fibrosis in diabetic rats and in diabetic rats treated with ramipril. This was accompanied by a significant reduction in active TGF-beta1 and phospho-Smad2/3 protein levels in myocardial tissue of diabetic rats. Echocardiography showed that diabetes was associated with increased end-systolic diameters, and depressed global systolic function and diastolic dysfunction, as assessed by transmitral Doppler velocity profile. These changes were completely reversed by insulin or ramipril treatment. Ac-SDKP treatment partially restored diastolic function in diabetic rats. In conclusion, Ac-SDKP administration in diabetic rats reduces left ventricular interstitial and perivascular fibrosis, active TGF-beta1 and phospho-Smad2/3levels, and improves diastolic function. Taken together, these findings suggest that, by inhibiting theTGF-beta/Smad pathway, Ac-SDKP protects against the development of diabetic cardiomyopathy

The growth factor midkine regulates the renin-angiotensin system in mice

The renin-angiotensin system plays a pivotal role in regulating blood pressure and is involved in the pathogenesis of kidney disorders and other diseases. Here, we report that the growth factor midkine is what we believe to be a novel regulator of the renin-angiotensin system. The hypertension induced in mice by 5/6 nephrectomy was accompanied by renal damage and elevated plasma angiotensin II levels and was ameliorated by an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin receptor blocker. Notably, ACE activity in the lung, midkine expression in the lung, and midkine levels in the plasma were all increased after 5/6 nephrectomy. Exposure to midkine protein enhanced ACE expression in primary cultured human lung microvascular endothelial cells. Furthermore, hypertension was not induced and renal damage was less severe in midkine-deficient mice. Supplemental administration of midkine protein to midkine-deficient mice restored ACE expression in the lung and hypertension after 5/6 nephrectomy. Oxidative stress might be involved in midkine expression, since expression of NADH/NADPH oxidase-1, -2, and -4 was induced in the lung after 5/6 nephrectomy. Indeed, the antioxidative reagent tempol reduced midkine expression and plasma angiotensin II levels and consequently ameliorated hypertension. These results suggest that midkine regulates the renin-angiotensin system and mediates the kidney-lung interaction after 5/6 nephrectomy.

Beyond immunosuppression – challenges in the clinical management of lupus nephritis

Lupus nephritis remains the most common severe manifestation of SLE with increased risk of death and end-stage renal disease. Although, recent research has focused on the choice of immunosuppressive in its treatment, other factors, including the quality and delivery of healthcare, the management of glucocorticoids and co-morbidity are probably of more importance. There has been significant progress in induction regimes with the successful use of mycophenolate mofetil, low dose intravenous cyclophosphamide and development of sequential regimens whereby cyclophosphamide is followed by an alternative immunosuppressive. However, the attention on the day-to-day management of lupus nephritis in the clinic has merited less attention. In this article, we aim to address more widely the major issues which are encountered regularly in the long-term management of these patients. The overall goals are the reduction of mortality and preservation of renal function.

Comorbidity in patients undergoing coronary artery bypass graft surgery: impact on outcome and implications for cardiac rehabilitation

The increasing comorbid disease burden among patients undergoing coronary artery bypass graft surgery (CABG) and the improved operative survival are expanding the number of post-CABG patients living with prognostically significant comorbidities. In a large contemporary database, 29.9% of the patients receiving isolated CABG had diabetes mellitus, 16% peripheral vascular disease, 18.6% chronic obstructive pulmonary disease, and 27.5% renal dysfunction. Patients with comorbidity are more likely to be old and often female, may have special care-requirements early after discharge, and are at increased risk for adverse outcomes. Contemporary available evidence indicates that older individuals, women, and patients with comorbidities are significantly less likely to receive cardiac rehabilitation. In addition, compliance with proven atherosclerosis risk reduction strategies for CABG patients is suboptimal. In this article we will review the impact of comorbidity on short-term and long-term outcome after CABG and their implications for cardiac rehabilitation.

Effects of soy protein hydrolysate on blood pressure and angiotensin-converting enzyme activity in rats with chronic renal failure

We investigated the effects of soy protein and soy protein hydrolysate on blood pressure control, angiotensin-converting enzyme (ACE) activity, and renal function in a rat chronic renal failure model. Rats that had undergone a 5/6 nephrectomy were separated into three groups and fed different experimental diets for 14 weeks. At the end of the study, rats that fed a diet containing soy protein as the protein source had better blood pressure control and renal function, as well as lower circulating ACE activity and renal tumor-necrosis factor-alpha (TNF-alpha) concentration than rats fed a casein protein diet. Soy protein hydrolysate was shown to be as effective as soy protein in preventing the elevation of blood pressure, the progression of renal failure, and decreases in kidney TNF-alpha level, plasma ACE activity, and insulin concentration. In conclusion, the beneficial effects of consuming soy protein on blood pressure and renal function may be mediated mostly by its pepsin-digested hydrolysate through its ACE inhibitory activity.

Multiorgan-protective actions of blockers of the renin-angiotensin system, statins and erythropoietin: common pleiotropic effects in reno-, cardio- and neuroprotection

Renal diseases induce nephroprotective measures that may affect the heart, brain and other organs. In addition, many cardiovascular and neurological diseases are accompanied by renal lesions. For these reasons, multiorgan-protective measures, including cardio-, reno- and neuro-protective measures, are necessary to treat these diseases. The drugs used in nephrology are often pleiotropic. Although they usually address a single organ or tissue, many of them have complex actions that may provide multiorgan-protection. The present paper aims to review 3 classes of drugs that are commonly prescribed in nephrological practice: statins, RAS blockers (such as ACEIs and ARBs) and erythropoietin (EPO). This paper highlights the renoprotective actions, as well as those that are protective of the heart, brain and other organs, of these drugs at the cellular and molecular level. Their protective actions are attributable to their main effects and pleiotropic effects. The protective pleiotropic actions of these drugs may be exerted on multiple organs, making them multiorgan-protective. Another objective is to analyse the shared multiorgan-protective pleiotropic effects of RAS blockers (ACEIs and ARBs), statins and erythropoietin. This will allow for the practical association of the main renoprotective drugs with multiorgan protection.

Diabetic nephropathy in children and adolescents

Type 1 diabetes mellitus (T1DM) commonly occurs in childhood or adolescence, although the rising prevalence of type 2 diabetes mellitus (T2DM) in these age groups is now being seen worldwide. Diabetic nephropathy (DN) develops in 15-20% of subjects with T1DM and in similar or higher percentage of T2DM patients, causing increased morbidity and premature mortality. Although overt DN or kidney failure caused by either type of diabetes are very uncommon during childhood or adolescence, diabetic kidney disease in susceptible patients almost certainly begins soon after disease onset and may accelerate during adolescence, leading to microalbuminuria or incipient DN. Therefore, all diabetics warrant ongoing assessment of kidney function and screening for the earliest manifestations of renal injury. Pediatric health care professionals ought to understand about risk factors, strategy for prevention, method for screening, and treatment of early DN. This review considers each form of diabetes separately, including natural history, risk factors for development, screening for early manifestations, and strategy recommended for prevention and treatment of DN in children and adolescents.

Role of angiotensin-converting enzyme 2 and angiotensin(1-7) in 17beta-oestradiol regulation of renal pathology in renal wrap hypertension in rats

17beta-Oestradiol (E2)-mediated inhibition of angiotensin-converting enzyme (ACE) protects the E2-replete kidney from the progression of hypertensive renal disease. Angiotensin-converting enzyme 2 (ACE2), a homologue of ACE, counters the actions of ACE by catalysing the conversion of angiotensin II (Ang II) to angiotensin(1-7) [Ang(1-7)]. We investigated E2 regulation of ACE2 in the renal wrap (RW) model of hypertension in rats. After 6 weeks on a high-sodium diet (4% NaCl), the activity of ACE2 was reduced in the renal cortex by 31%, which was mirrored by similar decreases in ACE2 protein (30%) and mRNA expression (36%) in the ovariectomized RW rat (RW-OVX); E2 replacement prevented these effects. The RW-OVX rats exhibited greater renal injury, including 1.7-fold more tubulointerstitial fibrosis and 1.6-fold more glomerulosclerosis than E2-replete females (RW-Intact and RW-OVX+E2). Angiotensin(1-7) infusion prevented these exacerbating effects of ovariectomy on renal pathology; no differences in indicators of renal injury were observed between RW-OVX-Ang(1-7) and RW-Intact rats. These renal protective effects of Ang(1-7) infusion were not attributable to increased ACE2 activity or to changes in heart rate or body weight, since these parameters were unchanged by Ang(1-7) infusion. Furthermore, Ang(1-7) infusion did not attenuate renal injury by reducing mean arterial pressure (MAP), since infusion of the peptide did not lower MAP but rather caused a slight increase during a 6 week chronic treatment for Ang(1-7). These results suggest that E2-mediated upregulation of renal ACE2 and the consequent increased Ang(1-7) production contribute to E2-mediated protection from hypertensive renal disease. These findings have implications for E2-deficient women with hypertensive renal disease and suggest that therapeutics targeted towards increasing ACE2 activity and Ang(1-7) levels will be renal protective.

Angiotensin-(1-7) prevents activation of NADPH oxidase and renal vascular dysfunction in diabetic hypertensive rats

BACKGROUND/AIM

We examined the influence of chronic treatment with angiotensin-(1-7) [Ang-(1-7)] on renox (renal NADPH oxidase, NOX-4) and the development of renal dysfunction in streptozotocin-treated spontaneously hypertensive rats (diabetic SHR).

METHODS

Mean arterial pressure, urinary protein and vascular responsiveness of the isolated renal artery to vasoactive agonists were studied in vehicle- or Ang-(1-7)-treated SHR and diabetic SHR.

RESULTS

Ang-(1-7) decreased the elevated levels of renal NADPH oxidase (NOX) activity and attenuated the activation of NOX-4 gene expression in the diabetic SHR kidney. Ang-(1-7) treatment increased sodium excretion but did not affect mean arterial pressure in diabetic SHR. There was a significant increase in urinary protein (266 +/- 22 mg/24 h) in the diabetic compared to control SHR (112 +/- 13 mg/24 h) and treatment of diabetic SHR with Ang-(1-7) reduced the degree of proteinuria (185 +/- 23 mg/24 h, p < 0.05). Ang-(1-7) treatment also attenuated the diabetes-induced increase in renal vascular responsiveness to endothelin-1, norepinephrine, and angiotensin II in SHR, but significantly increased the vasodilation of the renal artery of SHR and diabetic SHR to the vasodilator agonists.

CONCLUSION

These results suggest that treatment with Ang-(1-7) constitutes a potential therapeutic strategy to alleviate NOX-mediated oxidative stress and to reduce renal dysfunction in diabetic hypertensive rats.

An update on non-peptide angiotensin receptor antagonists and related RAAS modulators

The renin-angiotensin-aldosterone-system (RAAS) is an important regulator of blood pressure and fluid-electrolyte homeostasis. RAAS has been implicated in pathogenesis of hypertension, congestive heart failure, and chronic renal failure. Aliskiren is the first non-peptide orally active renin inhibitor approved by FDA. Angiotensin Converting Enzyme (ACE) Inhibitors are associated with frequent side effects such as cough and angio-oedema. Recently, the role of ACE2 and neutral endopeptidase (NEP) in the formation of an important active metabolite/mediator of RAAS, ang 1-7, has initiated attempts towards development of ACE2 inhibitors and combined ACE/NEP inhibitors. Furukawa and colleagues developed a series of low molecular weight nonpeptide imidazole analogues that possess weak but selective, competitive AT1 receptor blocking property. Till date, many compounds have exhibited promising AT1 blocking activity which cause a more complete RAAS blockade than ACE inhibitors. Many have reached the market for alternative treatment of hypertension, heart failure and diabetic nephropathy in ACE inhibitor intolerant patients and still more are waiting in the queue. But, the hallmark of this area of drug research is marked by a progress in understanding molecular interaction of these blockers at the AT1 receptor and unraveling the enigmatic influence of AT2 receptors on growth/anti-growth, differentiation and the regeneration of neuronal tissue. Different modeling strategies are underway to develop tailor made molecules with the best of properties like Dual Action (Angiotensin And Endothelin) Receptor Antagonists (DARA), ACE/NEP inhibitors, triple inhibitors, AT2 agonists, AT1/TxA2 antagonists, balanced AT1/AT2 antagonists, and nonpeptide renin inhibitors. This abstract gives an overview of these various angiotensin receptor antagonists.