Fetal deaths in Alabama, 1974-1983: a birth weight-specific analysis. Obstet Gynecol. 1987;70:831-835. [PMID: 3684115 DOI: 10.1155/2013/519130]

The use of aliskiren as an antifibrotic drug in experimental models: A systematic review

Aliskiren is an oral antihypertensive medication that acts by directly inhibiting renin. High levels of circulating renin and prorenin activate the pathological signaling pathway of fibrosis. This drug also reduces oxidative stress. Thus, the aim of this systematic review is to analyze experimental studies that show the actions of aliskiren on fibrosis. PubMed and LILACS databases were consulted using the keywords aliskiren and fibrosis within the period between 2005 and 2017. Fifty-three articles were analyzed. In the heart, aliskiren attenuated remodeling, hypertrophy, inflammatory cytokines, collagen deposition, and oxidative stress. In the kidneys, there was a reduction in interstitial fibrosis, the infiltration of inflammatory cells, apoptosis, proteinuria, and in the recruitment of macrophages. In diabetic models, an improvement in the albumin/creatinine relationship and in the insulin pathway in skeletal muscles was observed; aliskiren was beneficial to pancreatic function and glucose tolerance. In the liver, aliskiren reduced fibrosis, steatosis, inflammatory cytokines, and collagen deposition. In the lung and peritoneal tissues, there was a reduction in fibrosis. Many studies have reported on the beneficial effects of aliskiren on endothelial function and arterial rigidity. A reduction in fibrosis in different organs is cited by many authors, which complies with the results found in this review. However, studies diverge on the use of the drug in diabetic patients. Aliskiren has antifibrotic potential in several experimental models, interfering with the levels of fibrogenic cytokines and oxidative stress. Therefore, its use in diseases in which fibrosis plays an important pathophysiological role is suggested.

Renin Activity in Heart Failure with Reduced Systolic Function-New Insights

Regardless of the cause, symptomatic heart failure (HF) with reduced ejection fraction (rEF) is characterized by pathological activation of the renin–angiotensin–aldosterone system (RAAS) with sodium retention and extracellular fluid expansion (edema). Here, we review the role of active renin, a crucial, upstream enzymatic regulator of the RAAS, as a prognostic and diagnostic plasma biomarker of heart failure with reduced ejection fraction (HFrEF) progression; we also discuss its potential as a pharmacological bio-target in HF therapy. Clinical and experimental studies indicate that plasma renin activity is elevated with symptomatic HFrEF with edema in patients, as well as in companion animals and experimental models of HF. Plasma renin activity levels are also reported to be elevated in patients and animals with rEF before the development of symptomatic HF. Modulation of renin activity in experimental HF significantly reduces edema formation and the progression of systolic dysfunction and improves survival. Thus, specific assessment and targeting of elevated renin activity may enhance diagnostic and therapeutic precision to improve outcomes in appropriate patients with HFrEF.

Feasibility of fluorescence energy transfer system for imaging the renoprotective effects of aliskiren in diabetic mice

Introduction:

We investigated the feasibility of using a fluorescence resonance energy transfer system to image enzymatic activity in order to evaluate the effects of aliskiren (a direct renin inhibitor) on diabetic nephropathy.

Materials and methods:

First, we induced diabetes in C57BL/6J mice using streptozotocin, then treated them with either aliskiren (25 mg/kg/day) or the angiotensin type 1 receptor blocker valsartan (15 mg/kg/day) for four weeks. Finally, we utilized renin fluorescence resonance energy transfer substrate to assess renin activity.

Results:

Renin activity was much higher in the kidneys of diabetic mice compared to those of the non-diabetic control mice. While aliskiren inhibited this activity, valsartan did not. We noted that production of reactive oxygen species intensified and the bioavailability of nitric oxide diminished in the glomeruli of diabetic mice. Aliskiren and valsartan significantly ameliorated these effects. They suppressed glomerular production of reactive oxygen species and urinary albumin excretion. In fact, urinary albumin excretion in diabetic mice treated with aliskiren or valsartan was lower than that in untreated diabetic mice. Furthermore, aliskiren and valsartan significantly reduced glomerular permeability by maintaining the glomerular endothelial surface layer.

Conclusion:

Fluorescence resonance energy transfer could provide a new tool for evaluating tissue and plasma enzymatic activity.

Pathogenesis and treatment of chronic kidney disease: a review of our recent basic and clinical data

Chronic kidney disease (CKD) is a worldwide public health problem that affects millions of people from all racial and ethnic groups. At end of 2013, over 300,000 Japanese patients had maintenance dialysis therapy (JSDT). In Japan, the major causes of end stage kidney disease (ESKD) are chronic glomerulonephritis (particularly IgA nephropathy), type 2 diabetic nephropathy, and hypertensive nephrosclerosis. Hypertension is a major factor driving the progression of CKD to ESKD. Since many features of the pathogenesis of IgA nephropathy are still obscure, specific treatment is not yet available. However, efforts by investigators around the world have gradually clarified different aspects of the pathogenesis and treatment of IgA nephropathy. Today, around half of all diabetic patients in Japan receive medical treatment. Type 2 diabetic nephropathy is one of the major long-term microvascular complications occurring in nearly 40% of Japanese diabetic patients. The pathogenesis of diabetic nephropathy involves both genetic and environmental factors. However, the candidate genes related to the initiation and progression of the disorder are still obscure in patients with diabetic nephropathy. Regarding environmental factors, the toxicity of persistent hyperglycemia, reactive oxygen species, systemic and/or glomerular hypertension, dyslipidemia and complement are considered to play an important role. The first part of this review covers the pathogenesis of IgA nephropathy and type 2 diabetic nephropathy, and combines the clinicopathological findings in patients with our research on the ddY and KKA-y mouse models (spontaneous animal models for IgA nephropathy and diabetic nephropathy, respectively). In Japan, the major renal replacement therapies (RRT) are peritoneal dialysis (PD) and hemodialysis (HD). The second part of this review focuses on PD and HD. Based on our research findings from patients and as well as from animal models, we discuss strategies for the management of patients on PD and HD.

Protective effects of aliskiren, a direct renin inhibitor, in rats with acute pancreatitis

AIM: To investigate the inhibitory effects of aliskiren on the renin angiotensin system (RAS) in rats with acute pancreatitis (AP) and to explore the mechanisms involved.

METHODS: Seventy-two SD rats were randomly divided into a sham operation group, an acute AP model group, and an aliskiren therapy group. AP was induced by retrograde injection of 3.5% sodium taurocholate (0.1 mL/100 g) into the biliopancreatic duct. Aliskiren solution was administered in rats of the aliskiren therapy group by gavage at a dose of 20 mg/kg, and equivalent volume of normal saline (NS) was given in the other two groups. Rats in each group were further divided into three subgroups for taking inferior vena cava blood samples at 6, 12 and 24 h, respectively. The rats were then killed to observe pancreatic pathological changes and measure serum amylase (AMY), tumor necrosis factor-α (TNF-α), angiotensin Ⅱ (Ang Ⅱ), and plasma renin activity (PRA). The expression of nuclear factor kappa-B (NF-kB) and angiotensin Ⅱ type 1 receptor (AT1R) in the pancreas was determined by immunohistochemistry．

RESULTS: Compared with the AP group, pancreatic histopathological score (7.25 ± 0.80, 9.57 ± 1.54, 12.75 ± 1.22), AMY (2230.87 U/L ± 224.71 U/L, 2137.41 U/L ± 193.31 U/L, 2457.01 U/L ± 188.81 U/L), TNF-α (26.28 ng/L ± 2.45 ng/L, 27.51 ng/L ± 1.91 ng/L, 27.17 ng/L ± 2.02 ng/L), PRA [7.31 ng/(mL•h) ± 1.94 ng/(mL•h), 8.69 ng/(mL•h) ± 1.78 ng/(mL•h), 9.04 ng/(mL•h) ± 1.78 ng/(mL•h)], Ang Ⅱ (755.47 ng/L ± 121.33 ng/L, 871.17 ng/L ± 129.43 ng/L, 878.39 ng/L ± 81.29 ng/L), positive rates of AT1R (48.60 ± 6.28, 49.62 ± 7.19, 51.20 ± 7.04) and NF-κB (65.66 ± 4.93, 68.66 ± 5.23, 68.13 ± 7.14) at each time point (6, 12, 24 h) were decreased significantly (P < 0.05 for all) in the aliskiren therapy group.

CONCLUSION: Aliskiren can protect from pancreatic inflammation and injury in AP rats.

Role of the TNF pathway in the progression of diabetic nephropathy in KK-A(y) mice

Chronic inflammation promotes the progression of diabetic nephropathy (DN). However, the role of TNF-α remains unclear. The objectives of the present study were to examine whether TNF-α inhibition with a soluble TNF receptor (TNFR)2 fusion protein, i.e., etanercept (ETN), improves the early stage of DN in the type 2 diabetic model of the KK-A(y) mouse and to also investigate which TNF pathway, TNFR1 or TNFR2, is predominantly involved in the progression of this disease. ETN was injected intraperitoneally into mice for 8 wk. Renal damage was evaluated by immunohistochemistry, Western blot analysis, and/or real-time PCR. In vitro, mouse tubular proximal cells were stimulated by TNF-α and/or high glucose (HG) and treated with ETN. ETN dramatically improved not only albuminuria but also glycemic control. Renal mRNA and/or protein levels of TNFR2, but not TNF-α and TNFR1, in ETN-treated KK-A(y) mice were significantly decreased compared with untreated KK-A(y) mice. mRNA levels of ICAM-1, VCAM-1, and monocyte chemoattractant protein-1 and the number of F4/80-positive cells were all decreased after treatment. Numbers of cleaved caspase-3- and TUNEL-positive cells in untreated mice were very few and were not different from ETN-treated mice. In vitro, stimulation with TNF-α or HG markedly increased both mRNA levels of TNFRs, unlike in the in vivo case. Furthermore, ETN partly recovered TNF-α-induced but not HG-induced TNFR mRNA levels. In conclusion, it appears that ETN may improve the progression of the early stage of DN predominantly through inhibition of the anti-inflammatory action of the TNF-α-TNFR2 pathway.