Effects of Aliskiren on Blood Pressure, Albuminuria, and(Pro)Renin Receptor Expression in Diabetic

TG(mRen-2)27 RatsDavid L. Feldman, Liang Jin, Hong Xuan, Aurelie Contrepas, Yinong Zhou, Randy L. Webb,

Dominik N. Mueller, Sandra Feldt, Frederick Cumin, Wieslawa Maniara, Elke Persohn,Helmut Schuetz, A.H. Jan Danser, Genevieve Nguyen

Abstract—The aim of this study was to explore the effects of the renin inhibitor aliskiren in streptozotocin-diabeticTG(mRen-2)27 rats. Furthermore, we investigated in vitro the effect of aliskiren on the interactions between renin andthe (pro)renin receptor and between aliskiren and prorenin. Aliskiren distributed extensively to the kidneys ofnormotensive (non)diabetic rats, localizing in the glomeruli and vessel walls after 2 hours exposure. In diabeticTG(mRen-2)27 rats, aliskiren (10 or 30 mg/kg per day, 10 weeks) lowered blood pressure, prevented albuminuria, andsuppressed renal transforming growth factor-� and collagen I expression versus vehicle. Aliskiren reduced (pro)reninreceptor expression in glomeruli, tubules, and cortical vessels compared to vehicle (in situ hybridization). In humanmesangial cells, aliskiren (0.1 �mol/L to 10 �mol/L) did not inhibit binding of 125I-renin to the (pro)renin receptor, nordid it alter the activation of extracellular signal-regulated kinase 1/2 by renin (20 nmol/L) preincubated with aliskiren(100 nmol/L) or affect gene expression of the (pro)renin receptor. Evidence was obtained that aliskiren binds to theactive site of prorenin. The above results demonstrate the antihypertensive and renoprotective effects of aliskiren inexperimental diabetic nephropathy. The evidence that aliskiren can reduce in vivo gene expression for the (pro)reninreceptor and that it may block prorenin-induced angiotensin generation supports the need for additional work to revealthe mechanism of the observed renoprotection by this renin inhibitor. (Hypertension. 2008;52:130-136.)

Key Words: aliskiren � renin inhibitor � TG(mRen-2)rat � diabetic nephropathy � (pro)renin receptor

A central role for the renin-angiotensin-aldosterone sys-tem (RAAS) in the pathogenesis of diabetic nephropa-

thy (DN) is widely accepted, based largely on the attenuationof DN by angiotensin (Ang) converting enzyme inhibitors(ACEi)1 and Ang II receptor blockers (ARB).2 However,these agents do not halt renal decline, possibly because ofinsufficient suppression of the intrarenal RAAS. Theoreti-cally, agents that more effectively suppress the RAAS shouldconfer improved tissue protection over current treatments forDN. Renin inhibitors, by acting at the point of activation ofthe RAAS cascade, may represent such agents. Aliskiren is apotent inhibitor of human renin; it lowers blood pressure (BP)in patients with mild-moderate hypertension3,4 and showscardiorenal protection in hypertensive double transgenic ratsexpressing human genes for renin and angiotensinogen.5

The cloning of a functional receptor for renin and prorenin[(P)RR]6 suggests that renin and prorenin [collectively, (pro)renin] may exert direct (receptor-mediated, Ang II–indepen-

dent) tissue-damaging effects by increasing the expression ofprofibrotic pathways7 and molecules such as TGF-beta1

(TGF-�1).8 Moreover, prorenin, the inactive proenzyme formof renin, may contribute to tissue damage9,10 via binding toand activation of the (P)RR. On binding to the (P)RR,prorenin undergoes nonproteolytic activation,6,11 a conforma-tional change that exposes its active site without removal ofthe prosegment.12,13 This permits cell surface generation ofAng-I,6,11 and via subsequently formed Ang II, may contrib-ute to the development of DN.14,15 Additionally, the (P)RRmay amplify renin-induced Ang II–dependent effects; reninbound to the (P)RR gains �5 fold enhanced catalytic activityversus soluble renin.6

TG(mRen-2)27 rats express the mouse ren-2 gene andbecome hypertensive.16 When rendered diabetic with strep-tozotocin (STZ), they develop renal damage consideredanalogous to that seen in human DN.17 Aliskiren showsantihypertensive and renoprotective effects in this model.18

Received December 14, 2007; first decision January 12, 2008; revision accepted April 16, 2008.From Novartis Institutes for Biomedical Research (D.L.F., L.J., H.X., Y.Z., R.L.W., F.C., W.M.), E. Hanover, NJ and Cambridge, Mass; Inserm Unit

833 (A.C., G.N.), Paris, France; Chaire de Medecine Experimentale (A.C., G.N.), College de France, Paris, France; Max-Delbruck-Center (D.N.M., S.F.),Berlin-Buch, Germany; Novartis Pharma AG (E.P., H.S.), Basel, Switzerland; and the Department of Pharmacology (A.H.J.D.), Erasmus MC, Rotterdam,The Netherlands.

Correspondence to David L. Feldman, PhD, Novartis Institutes for Biomedical Research, Bldg 437, Rm 3317, One Health Plaza, E Hanover, NJ 07936.E-mail david.feldman@novartis.com

© 2008 American Heart Association, Inc.

Hypertension is available at http://hyper.ahajournals.org DOI: 10.1161/HYPERTENSIONAHA.107.108845

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Here we explored potential renoprotective mechanisms ofaliskiren in diabetic TG(mRen-2)27 rats. Thus, we confirmedthe antihypertensive and antialbuminuric effects of aliskiren,determined its renophilic nature, and studied whether thisrenin inhibitor can (1) bind to the active site of prorenin invitro; (2) interfere with the binding of renin to the (P)RR invitro; and (3) alter the gene expression of renal (P)RR,TGF-�1, and collagen I in vivo.

Materials and MethodsFor details of the methods and statistical procedures please seehttp://hyper.ahajournals.org.

In Vitro Studies

Determination of IC50 of Aliskiren Against Mouse ReninThe IC50 for aliskiren against mouse submaxillary gland renin19 wasdetermined by measuring the rate of cleavage of the fluorescence-quenched substrate RE(EDANS)IHPFHLVIHTK(Dabcyl)R (Bio-synthan GmbH).

Ability of Aliskiren to Bind to Active Site of ProreninProrenin exists in 2 conformations: a catalytically inactive form,where the prosegment covers the active site (“closed”), and an“open” conformation where the prosegment does not cover the activesite, permitting access to substrate. Open prorenin is catalyticallyactive and recognizable by antibodies directed against epitopes in theactive site.12 Thus, aliskiren-enhanced antibody binding to proreninwould indicate binding of aliskiren to the active site of prorenin,thereby preventing the prosegment from returning to its “closed”position.

We applied an immunoradiometric assay12 to determine the abilityof increasing aliskiren concentrations (�10 �mol/L) to bind toprorenin from a pool of human plasma.

Effect of Aliskiren on Binding of Renin to (P)RR, onERK Activation, and Gene Expression of (P)RR inMesangial CellsFor each experiment, human mesangial cells6,7 were exposed for 4hours at 19°C (prevents internalization) � cold renin (100 nmol/L)to 125I-renin (1 nmol/L), or to 125I-renin that was untreated orpreincubated with aliskiren (0.1 �mol/L to 10 �mol/L). Specificbinding of renin was determined by subtracting nonspecific bindingfrom total renin binding.

Phosphorylation of ERK 1/2 was studied by immunoblotting6 incells exposed to renin (20 nmol/L)�preincubation for 30 minutes at37°C with excess aliskiren (100 nmol/L).

To determine whether aliskiren could alter gene expression of(P)RR in vitro, mesangial cells were incubated with 1 �mol/Laliskiren for 24 hours, mRNA was extracted, and real-time (quanti-tative) RT-PCR was performed to assess gene expression of (P)RR.

In Vivo StudiesAnimal procedures conformed to guidelines of the Novartis AnimalCare and Use Committee.

Renal Partitioning and Localization of Aliskiren in RatsStreptozotocin-induced diabetic male Sprague-Dawley (S-D) ratsand normoglycemic controls were used. Aliskiren treatment (3, 10mg/kg day by subcutaneously implanted osmotic Alzet minipumps)commenced 1 day after induction of diabetes. Two weeks lateranimals were euthanized and kidneys were removed for measure-ment of aliskiren levels.

To identify the potential renal compartments accessible toaliskiren, 2 normal male Hanover Wistar rats received a single i.v.dose of 14C-aliskiren (10 mg/kg). Two hours later the rats wereeuthanized and the kidneys were removed and snap frozen. Subse-quently, 10-�m-thick cryosections were processed for autoradiogra-

phy. Labeling at the light microscopic level was defined by moresilver grains over the tissue than the background without tissue.

Effect of Aliskiren on Diabetic TG(mRen-2)27 RatsTG(mRen-2)27 rats were implanted with radiotelemetry devices at7.5 to 8.5 weeks old for measuring BP.20 About 1 week later baselinealbumin levels were determined, diabetes was induced, and the nextday the rats received vehicle (PBS) or aliskiren (10, 30 mg/kg perday) as above. Doses were chosen from preliminary studies inTG(mRen-2)27 rats. After 10 weeks of treatment all animals wereeuthanized, the kidneys were removed rapidly and fixed in formalinfor in situ hybridization,21 or snap frozen for studying gene expres-sion of TGF-�1, collagens I, III, IV, and rat renin by quantitativePCR.

ResultsIn Vitro StudiesEffect of Aliskiren on Nonproteolytic Activationof ProreninIn the absence of aliskiren, the plasma pool contained 12 mU/Lrenin and 163 mU/L prorenin. In the presence of aliskiren theamount of immunoreactive renin increased in an aliskirenconcentration-dependent manner (Figure 1). Thus, aliskiren iscapable of binding to the active site of prorenin.

Effect of Aliskiren on Binding of Renin to (P)RR, onERK Activation, and Gene Expression of (P)RRSpecific binding of renin to the (P)RR was not altered byaliskiren at either 1 �mol/L (Figure 2A) or 10 �mol/Laliskiren (data not shown), confirming that the active site ofrenin is not involved in the binding.7 When renin (20 nmol/L)was preincubated with excess aliskiren before adding to themesangial cells, ERK activation was not modified versusnonpreincubated renin (Figure 2B). Aliskiren treatment ofmesangial cells did not alter gene expression of (P)RR(Figure 2C).

In Vivo StudiesRenal Partitioning and Localization of Aliskiren inS-D RatsPlasma levels of aliskiren in S-D rats treated with thecompound for 2 weeks were 126�16 ng/mL in nondiabetic

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Figure 1. Aliskiren binds to the active site of prorenin. Percent-age of prorenin detected as active renin after incubation withaliskiren (indicating relative amount of prorenin bound toaliskiren) is shown. Pooled plasma containing (pro)renin wasincubated with increasing concentrations of aliskiren. One hun-dred percent prorenin activation represents the amount of pro-renin detected as renin after cleaving the prosegment with tryp-sin, ie, the maximum amount of prorenin that can be affected byaliskiren.

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rats (10 mg/kg per day) and 29.5�4.6 ng/mL and 128�22.7ng/mL in diabetic rats (3, 10 mg/kg per day, respectively).The mean kidney/plasma concentration ratio of aliskiren inrats treated with the compound for 2 weeks was 45.7 fornondiabetic rats (10 mg/kg per day) and was 30.8 and 63.7 fordiabetic rats (3, 10 mg/kg per day, respectively; Figure 3A),indicating extensive partitioning of aliskiren to the kidneys.In rats treated with 10 mg/kg per day of aliskiren, renalcontent of aliskiren was lower in diabetic versus nondiabeticrats, but plasma levels of aliskiren were similar.

By light microscopy, 100% of glomeruli on each renalsection showed localization of autoradiographic grains, indi-cating the presence of aliskiren (Figure 3B). The cell type inwhich aliskiren was localized could not be determined fromthe 10-�m-thick frozen sections used in our study. Regard-less, the pattern did not resemble an exclusively luminaldistribution. Extensive labeling was also found in the arterialwall of the small cortical vessels in the kidney (Figure 3C).

Effect of Aliskiren in Diabetic TG(mRen-2)27 Rats

IC50 of Aliskiren Against Mouse ReninThe IC50 for aliskiren against mouse renin was determined tobe 4.5 nmol/L, confirming that aliskiren effectively inhibitsthe enzymatic activity of mouse renin.

Body Weight and Blood GlucoseAt the end of the study, diabetic TG(mRen-2)27 rats showedno statistically significant differences between groups in bodyweight or gain in body weight.

The intended level of glucose control (400 to 525 mg/dL)was achieved during the study. Areas under the bloodglucose versus time curves were not significantly differentbetween groups (Table S1).

Effect of Aliskiren on BP, Heart Rate, AlbuminuriaThere was a trend for a mild and gradual decline22 in meanarterial pressure (MAP) in vehicle-treated diabeticTG(mRen-2)27 rats during the study (Figure 4A). In contrast,

Figure 2. A through C, Aliskiren does not block renin binding to (P)RR, nor does it affect renin-induced ERK activation or gene expres-sion of (P)RR in mesangial cells. A, 125I-renin that was untreated or preincubated with aliskiren (0.1 �mol/L to 10 �mol/L) was added tohuman mesangial cells with or without cold renin (100 nmol/L). The binding was conducted for 4 hours at 19°C. Specific binding ofrenin was determined by subtracting nonspecific binding from total renin binding. Results are representative of 3 experiments. B,Serum-starved mesangial cells were exposed to renin (20 nmol/L) that had or had not been preincubated with excess aliskiren (100nmol/L) for the indicated times. Cell lysates were analyzed for phosphorylated and total ERK1/2 by immunoblotting techniques. Resultsare representative of 3 experiments. C, Mesangial cells were incubated with 1 �mol/L aliskiren for 24 hours, mRNA was extracted, andquantitative PCR was performed to assess gene expression of (P)RR. Data are expressed as Arbitrary Units (AU) after standardizationagainst GAPDH. Results are representative of 3 experiments.

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initiation of treatment with aliskiren resulted in a prompt andsustained reduction in MAP. Five days after starting treat-ment with aliskiren, average MAP was reduced by 36�4 and51�3 mm Hg by aliskiren 10 and 30 mg/kg per day,respectively. The antihypertensive effect of aliskiren ap-peared to be dose-related for the initial 4 weeks of treatment,after which an additional BP lowering effect was noted inboth groups.

Heart rates were not significantly affected by aliskirentreatment (data not shown).

At the start of the study albuminuria did not differsignificantly between the groups. The progressive albumin-uria seen in vehicle-treated TG(mRen-2)27 rats did notdevelop in aliskiren-treated TG(mRen-2)27 rats (Figure 4B).

Effect of Aliskiren on Renal Cortical Gene Expression ofTGF-�1, Collagen I, III, IV, and (P)RRAt the end of the study, renal cortical gene expression ofTGF-�1 was significantly suppressed in aliskiren- versusvehicle-treated diabetic TG(mRen-2)27 rats (Figure 5A), withthe 10 mg/kg per day group tending to be slightly but not

significantly greater than in the 30 mg/kg per day group.Renal gene expression of collagen I was significantly reducedby treatment of diabetic TG(mRen-2)27 rats with bothaliskiren doses (Figure 5B). Expression of collagens III andIV was not significantly altered by aliskiren treatment com-pared to vehicle-treated diabetic TG(mRen-2)27 rats (data notshown).

In situ hybridized renal sections from vehicle-treated dia-betic TG(mRen-2)27 rats showed prominent labeling for(P)RR in glomeruli and tubules and less in renal arteries(Figure 6A, 6C, 6E). However, in aliskiren-treatedTG(mRen-2)27 rats, expression of (P)RR in these renalcompartments was markedly suppressed compared tovehicle-treated controls (Figure 6B, 6D, 6F).

Effect of Aliskiren on Gene Expression of Renal Rat ReninAt the end of the study gene expression of endogenous ratrenin was significantly and dose-dependently increased abovevehicle-treated rats (Figure 7), indicating aliskiren-inducedRAAS blockade.

DiscussionThe main findings in this study were that in a model ofhypertensive diabetic renal damage, renin inhibition withaliskiren lowered BP, prevented albuminuria, and suppressedrenal gene expression of the (P)RR. Moreover, aliskirendisplayed the potential to inhibit prorenin. Thus, aliskirenmay exert multiple renoprotective mechanisms.

In TG(mRen-2)27 rats, mouse renin contributes to theelevated BP.16,23 Thus, the observed inhibitory potency ofaliskiren against mouse renin (IC50 4.5 nmol/L) suggests thataliskiren lowered BP in TG(mRen-2)27 rats by inhibitingmouse renin. The increased renal gene expression of (endog-enous) rat renin in these animals, indicating RAAS blockade,further supports this assertion.

The extensive partitioning of aliskiren to the kidneyssuggests a renoprotective effect via inhibiting the intrarenalRAAS, in addition to the antihypertensive effect of the drug.Moreover, the localization of autoradiographic grains inglomeruli and the vascular wall, indicating the presence ofaliskiren, suggests the potential for local renin inhibitionwithin these structures. Longer exposures to aliskiren mayresult in localization of the drug in other renal compartmentssuch as the tubulo-interstitium. Importantly, the presence ofaliskiren in the vessel wall suggests that aliskiren may enterthe juxtaglomerular cells of the afferent arteriole, the site ofrenin synthesis, opening the possibility that aliskiren mightinhibit forming (or formed, but still intracellular) renin evenbefore its release from juxtaglomerular cells. Indeed, block-ade of intracellular renin by aliskiren has been reported incultured cardiomyoctes.24

Recently Kelly et al18 reported in diabetic TG(mRen-2)27rats that despite not lowering BP to the same extent as theACEi perindopril, the administered dose of aliskiren attenu-ated tubulo-interstitial fibrosis to a greater extent than theACEi and reduced albuminuria and glomerulosclerosis tosimilar levels as the latter agent.

In our study, treatment of diabetic TG(mRen-2)27 rats withaliskiren also prevented, for the entire study, the development

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Figure 4. A and B, Aliskiren treatment reduces BP and preventsdevelopment of albuminuria in diabetic TG(mRen-2)27 rats.TG(mRen-2)27 rats were treated with vehicle or aliskiren for 10weeks. A, BP was measured by telemetry. Each point reflectsthe average MAP measured over 15 seconds every 10 minutes.P�0.05 for vehicle vs aliskiren groups (ANOVA). (n�6 to 7per group). B, Urinary albumin was determined by ELISA.Means�SEM, (n�6 to 7 per group). P�0.05: vehicle vs 10mg/kg per day (*); vs 30 mg/kg per day (†); vs 10 and 30 mg/kgper day (‡).

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of albuminuria that was seen in vehicle-treated controls.These findings are relevant because albuminuria is consid-ered a marker for risk of renal decline.25

The extent to which the antialbuminuric effect of aliskirenwas attributable to its antihypertensive effect per se, com-pared to a BP-independent effect, was not addressed in thisstudy.

TGF-�1 in conjunction with Ang II plays a central role inrenal fibrosis.26 Our data indicate that aliskiren suppressed therenal gene expression of TGF-�1 in vivo and thereby mayhave potential to inhibit TGF-�1–mediated pathways towardrenal fibrosis. Indeed, in our study aliskiren reduced renalcollagen I gene expression. The lack of corresponding effectson collagen III and IV may reflect a differential level ofsynthetic activity of these collagens at this stage in theexperimental model.

The recent cloning of the (P)RR6 and its implication incardio-renal disease14,15,21 prompted us to explore a possiblerelationship between renoprotection of aliskiren and thefunction of this receptor. Our in vitro results indicate thataliskiren, as with remikiren,7 did not induce a conformationalchange in the renin molecule extensive enough to interferewith a renin–(P)RR interaction. Thus, aliskiren is not a (P)RRantagonist, and the aliskiren-induced reduction in BP, renalTGF-�1, and collagen I expression, and the prevention ofalbuminuria are unlikely to result from inhibition of reninbinding to its receptor.

Despite the above in vitro findings, the observations by insitu hybridization indicate an aliskiren-induced suppressionof gene expression of (P)RR in vivo. Incubation ofaliskiren with mesangial cells did not alter gene expressionof (P)RR in these cells, arguing against a direct effect of

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Figure 5. A and B, Aliskiren treatment suppresses renal cortical gene expression for TGF-�1 and collagen I in diabetic TG(mRen-2)27rats. TG(mRen-2)27 rats were treated with vehicle or aliskiren for 10 weeks. Renal cortical TGF-�1 (A) and collagen I (B) gene expres-sions are expressed as % vehicle control after standardization against GAPDH.

Figure 6. Aliskiren treatment suppresses gene expression of (P)RR in diabetic TG(mRen-2)27 rats; in situ hybridization. Expression of(P)RR was prominent in glomeruli (A, B; 40�), tubules (C, D; 16�), and small cortical vessels (E, F; 40�) in vehicle-treated rats (A, C,E), but was reduced in aliskiren-treated rats (B, D, F; aliskiren 10 mg/kg per day).

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aliskiren on (P)RR expression in vivo. This lack of in vitroeffect may reflect the absence of physiological mechanismsthat may be required for aliskiren to indirectly reduce (P)RRexpression in vivo; possibly by (1) reducing renal/plasmaAng II levels, (2) increasing renal/plasma (pro)renin levels,(3) recruiting intracellular promyelocytic zinc finger,27 orsimply (4) by lowering BP.

The current in situ hybridization results show a distributionpattern in more renal compartments than initially described inhuman kidneys.6 However, our results are consistent with amore recent report of tubular expression of the (P)RR gene inhuman kidneys.28

Huang et al showed that in cultured mesangial cells,stimulation of the (P)RR with renin resulted in TGF-�1

production8 and extracellular matrix protein synthesis, andthat suppressing the (P)RR inhibited the production of theselatter factors.29 Our in vivo observations appear to be consis-tent with those findings. However, we emphasize that in thecurrent study a causal link between the salutary effectsinduced by aliskiren in TG(mRen-2)27 rats and the observedaliskiren-induced suppression of renal gene expression of the(P)RR is not clearly defined.

Diabetic TG(mRen-2)27 rats develop high levels of circu-lating prorenin by 4 weeks after STZ-induced diabetes,17 andthis prorenin may in part contribute to intrarenal angiotensingeneration.14 The current results indicate that (P)RR-mediated activation of prorenin and the consequent gain inAng II forming ability6 may be neutralized by aliskiren,because like other renin inhibitors,12 aliskiren bound to theactive site of prorenin. Once bound to “open” prorenin,aliskiren is unlikely to dissociate, because of its high affinityfor the active site. Moreover, this binding should block anyenzymatic activity gained by (non)-proteolytic activation ofthe molecule. Consequently, tissue damage related to angio-tensin generated by (P)RR-bound, nonproteolytically acti-vated prorenin, or prorenin that becomes proteolyticallyactivated at tissue sites should be reduced by aliskiren.

The present work supports the conclusion that, in diabeticTG(mRen-2)27 rats, aliskiren is an antihypertensive renopro-tective agent that does not act by interfering with the functionof the (P)RR. Thus, to the extent that the (P)RR may play arole in the pathogenesis of experimental DN,14,15 we specu-late that besides lowering systemic BP and blocking thecirculating and tissue RAAS, aliskiren may be antifibrotic bythe following nonmutually exclusive (P)RR-mediated ac-tions: (1) suppression of (P)RR gene expression may causeless receptor number and dampen intracellular fibrotic path-ways induced by (pro)renin, (2) preventing the activation ofprorenin in renal tissue, (3) negating the gain in catalyticactivity of receptor-bound renin. However, more work isneeded to determine whether the (P)RR plays a pathogenicrole in DN.

PerspectivesPatients treated with RAAS blocking agents, including aliskiren,show high concentrations of plasma renin. If the (P)RR isproven to be important in the pathogenesis of human DN, andif aliskiren suppresses expression of the (P)RR in humans,this action of aliskiren could mitigate the potentially negativeconsequences of renin-induced activation of the (P)RR.

AcknowledgmentsMary Arnella, Danielle Diaz, Rita Engler, Rocca Miserendino-Molteni, Hans-Joachim Handschin, and Stefan Schopfer providedexcellent technical assistance.

Source of FundingThis study was funded by Novartis Institutes for Biomedical Re-search, Inc.

DisclosuresD.L.F., L.J., H.X., Y.Z., R.L.W., F.C., W.M., E.P., and H.S. arefull-time employees of Novartis Institutes of Biomedical ResearchInc and Novartis Pharma AG, respectively. D.N.M., A.H.J.D., andG.N. are recipients of a research grant from Novartis Institutes forBiomedical Research.

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sin-converting-enzyme inhibition on diabetic nephropathy. The Collabo-rative Study Group. N Engl J Med. 1993;329:1456–1462.

2. Brenner BM, Cooper ME, de Zeeuw D, Keane WF, Mitch WE, ParvingH-H, Remuzzi G, Snapinn SM, Zhang Z, Shahinfar S, for the RENAALStudy Investigators Effects of losartan on renal and cardiovascularoutcomes in patients with type 2 diabetes and nephropathy. New EnglandJ Med. 2001;345:861–869.

3. Gradman A, Schmieder RE, Lins RL, Nussberger J, Chiang Y, BedigianMP. Aliskiren, a novel orally effective renin inhibitor, provides dose-dependent antihypertensive efficacy and placebo-like tolerability inhypertensive patients. Circulation. 2005;111:1012–1018.

4. Stanton A, Jensen C, Nussberger J, O’Brien E. Blood pressurelowering in essential hypertension with an oral renin inhibitor,aliskiren. Hypertension. 2003;42:1137–1143.

5. Pilz B, Shagdarsuren E, Wellner M, Fiebeler A, Dechend R, Gratze P,Meiners S, Feldman DL, Webb RL, Garrelds IM, Danser AHJ, Luft FC,Muller DN. Aliskiren, a human renin inhibitor, ameliorates cardiac andrenal damage in double-transgenic rats. Hypertension. 2005;46:569–576.

6. Nguyen G, Delarue F, Burckle C, Bouzhir L, Giller T, Sraer JD. Pivotalrole of the renin/prorenin receptor in angiotensin II production andcellular responses to renin. J Clin Invest. 2002;109:1417–1427.

7. Nguyen G, Delarue F, Berrou J, Rondeau E, Sraer JD. Specific receptorbinding of renin on human mesangial cells in culture increases plasmin-ogen activator inhibitor-1 antigen. Kid Int. 1996;50:1897–1903.

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N=5

p<0.001

p<0.007

Figure 7. Aliskiren treatment increases renal cortical rat reningene expression in diabetic TG(mRen-2)27 rats. TG(mRen-2)27 rats were treated with vehicle or aliskiren for 10 weeks.Renal cortical rat renin gene expression is expressed as %vehicle control after standardization against GAPDH.

Feldman et al Aliskiren and Experimental Diabetic Nephropathy 135

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Schuetz, A.H. Jan Danser and Genevieve NguyenDominik N. Mueller, Sandra Feldt, Frederick Cumin, Wieslawa Maniara, Elke Persohn, Helmut David L. Feldman, Liang Jin, Hong Xuan, Aurelie Contrepas, Yinong Zhou, Randy L. Webb,

in Diabetic TG(mRen-2)27 RatsEffects of Aliskiren on Blood Pressure, Albuminuria, and (Pro)Renin Receptor Expression

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