Exacerbation of acute kidney injury by bone marrow stromal cells from rats with persistent renin-angiotensin system activation.

Hypertension and persistent activation of the renin-angiotensin system (RAS) are predisposing factors for the development of acute kidney injury (AKI). Although bone-marrow-derived stromal cells (BMSCs) have shown therapeutic promise in treatment of AKI, the impact of pathological RAS on BMSC functionality has remained unresolved. RAS and its local components in the bone marrow are involved in several key steps of cell maturation processes. This may also render the BMSC population vulnerable to alterations even in the early phases of RAS pathology. We isolated transgenic BMSCs (TG-BMSCs) from young end-organ-disease-free rats with increased RAS activation [human angiotensinogen/renin double transgenic rats (dTGRs)] that eventually develop hypertension and die of end-organ damage and kidney failure at 8 weeks of age. Control cells (SD-BMSCs) were isolated from wild-type Sprague-Dawley rats. Cell phenotype, mitochondrial reactive oxygen species (ROS) production and respiration were assessed, and gene expression profiling was carried out using microarrays. Cells' therapeutic efficacy was evaluated in a rat model of acute ischaemia/reperfusion-induced AKI. Serum urea and creatinine were measured at 24 h and 48 h. Acute tubular damage was scored and immunohistochemistry was used for evaluation for markers of inflammation [monocyte chemoattractant protein (MCP-1), ED-1], and kidney injury [kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL)]. TG-BMSCs showed distinct mitochondrial morphology, decreased cell respiration and increased production of ROS. Gene expression profiling revealed a pronounced pro-inflammatory phenotype. In contrast with the therapeutic effect of SD-BMSCs, administration of TG-BMSCs in the AKI model resulted in exacerbation of kidney injury and high mortality. Our results demonstrate that early persistent RAS activation can dramatically compromise therapeutic potential of BMSCs by causing a shift into a pro-inflammatory phenotype with mitochondrial dysfunction.

Dexmedetomidine preconditioning ameliorates kidney ischemia-reperfusion injury.

Kidney ischemia-reperfusion (I/R) injury is a common cause of acute kidney injury. We tested whether dexmedetomidine (Dex), an alpha2 adrenoceptor (α2-AR) agonist, protects against kidney I/R injury. Sprague-Dawley rats were divided into four groups: (1) Sham-operated group; (2) I/R group (40 min ischemia followed by 24 h reperfusion); (3) I/R group + Dex (1 µg/kg i.v. 60 min before the surgery), (4) I/R group + Dex (10 µg/kg). The effects of Dex postconditiong (Dex 1 or 10 µg/kg i.v. after reperfusion) as well as the effects of peripheral α2-AR agonism with fadolmidine were also examined. Hemodynamic effects were monitored, renal function measured, and acute tubular damage along with monocyte/macrophage infiltration scored. Kidney protein kinase B, toll like receptor 4, light chain 3B, p38 mitogen-activated protein kinase (p38 MAPK), sirtuin 1, adenosine monophosphate kinase (AMPK), and endothelial nitric oxide synthase (eNOS) expressions were measured, and kidney transciptome profiles analyzed. Dex preconditioning, but not postconditioning, attenuated I/R injury-induced renal dysfunction, acute tubular necrosis and inflammatory response. Neither pre- nor postconditioning with fadolmidine protected kidneys. Dex decreased blood pressure more than fadolmidine, ameliorated I/R-induced impairment of autophagy and increased renal p38 and eNOS expressions. Dex downregulated 245 and upregulated 61 genes representing 17 enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, in particular, integrin pathway and CD44. Ingenuity analysis revealed inhibition of Rac and nuclear factor (erythroid-derived 2)-like 2 pathways, whereas aryl hydrocarbon receptor (AHR) pathway was activated. Dex preconditioning ameliorates kidney I/R injury and inflammatory response, at least in part, through p38-CD44-pathway and possibly also through ischemic preconditioning.

Skeletal muscle gene expression profile is modified by dietary protein source and calcium during energy restriction.

BACKGROUND/AIMS: The potential of whey protein and calcium to modify skeletal muscle gene expression during energy restriction (ER) was investigated in a model of diet-induced obesity. METHODS: Obese C57BL/6J mice received casein (calcium 0.4%) and two different high-calcium (1.8%) whey protein-based [whey protein isolate (WPI)+Ca and α-lactalbumin+Ca] diets for ER. RESULTS: Compared to casein, WPI and α-lactalbumin-based diets altered 208 and 287 genes, respectively, of which 186 genes were common to WPI and α-lactalbumin diets. These genes represented 31 KEGG pathways. The Wnt signaling was the most enriched pathway among the 101 genes regulated by α-lactalbumin only, whereas the 22 genes regulated by WPI only were not associated with KEGG pathways. Unlike casein, WPI and α-lactalbumin diets decreased Aldh1a7, Fasn, leptin, Nr4a3 and Scd1 mRNA expression, indicating dietary protein source-dependent alterations in muscle lipid and fatty acid metabolism. Muscle weight or lean body mass maintenance did not differ between groups although modest changes in hypertrophy/atrophy signaling were found. CONCLUSION: The skeletal muscle gene expression profile is modified by the dietary protein source and calcium during ER which may explain, at least in part, the greater anti-obesity effect of whey proteins and calcium compared to casein.

Effects of high-calcium diets with different whey proteins on weight loss and weight regain in high-fat-fed C57BL/6J mice.

The aim of the study was to compare the effect of different whey protein-containing high-Ca diets on weight loss and weight regain in a model of diet-induced obesity. Obesity was induced in C57BL/6J mice with a high-fat (60 % of energy) diet. Weight loss by energy restriction was performed on four different high-Ca diets (1.8 % CaCO3) containing different whey proteins (18 % of energy): alpha-lactalbumin (ALA), beta-lactoglobulin (BLG), lactoferrin (LF) and whey protein isolate (WPI). After 7 weeks of energy restriction some of the mice were killed and the rest were fed with the same diets ad libitum for 7 weeks. The mice on the LF diet lost significantly more weight than mice on the WPI diet. The body fat content in the ALA and LF groups was significantly lower than in the WPI group (P < 0.05) and the LF group differed significantly even from the BLG group (P < 0.05). Ad libitum feeding after weight loss resulted in weight regain in all groups and only the ALA diet significantly reduced fat accumulation during weight regain. The weight regain was most pronounced in the LF group, but the adipocyte size was still significantly smaller than in the other groups. There were no differences in food intake or apparent fat digestibility between the groups. It can be concluded that a high-Ca diet with ALA significantly improves the outcome of weight loss and subsequent weight regain during the feeding of a high-fat diet in C57BL/6J mice, in comparison with WPI.

Metabolomic changes in fatty liver can be modified by dietary protein and calcium during energy restriction.

AIM: To characterise the effect of energy restriction (ER) on liver lipid and primary metabolite profile by using metabolomic approach. We also investigated whether the effect of energy restriction can be further enhanced by modification of dietary protein source and calcium. METHODS: Liver metabolomic profile of lean and obese C57Bl/6J mice (n = 10/group) were compared with two groups of weight-reduced mice. ER was performed on control diet and whey protein-based high-calcium diet (whey + Ca). The metabolomic analyses were performed using the UPLC/MS based lipidomic platform and the HPLC/MS/MS based primary metabolite platform. RESULTS: ER on both diets significantly reduced hepatic lipid accumulation and lipid droplet size, while only whey + Ca diet significantly decreased blood glucose (P < 0.001) and serum insulin (P < 0.01). In hepatic lipid species the biggest reduction was in the level of triacylglycerols and ceramides while the level of cholesterol esters was significantly increased during ER. Interestingly, diacylglycerol to phospholipid ratio, an indicator of relative amount of diabetogenic diglyceride species, was increased in the control ER group, but decreased in the whey + Ca ER group (P < 0.001, vs obese). ER on whey + Ca diet also totally reversed the obesity induced increase in the relative level of lipotoxic ceramides (P < 0.001, vs obese; P > 0.05, vs lean). These changes were accompanied with up-regulated TCA cycle and pentose phosphate pathway metabolites. CONCLUSION: ER-induced changes on hepatic metabolomic profile can be significantly affected by dietary protein source. The therapeutic potential of whey protein and calcium should be further studied.

Effect of dietary calcium and dairy proteins on the adipose tissue gene expression profile in diet-induced obesity.

BACKGROUND/AIMS: Calcium and dairy proteins have been postulated to explain why the intake of dairy products correlates inversely with body mass index in several populations. We have shown that a high-calcium diet with whey protein attenuates weight gain and now we describe the effects of this diet on adipose tissue gene expression. METHODS: Nine-week-old C57Bl/6J mice were divided into two groups (n = 10/group). The control diet was a standard high-fat diet (60% of energy) low in calcium (0.4%). The whey protein diet was a high-calcium (1.8%), high-fat diet with whey protein. After the 21-week treatment, adipose tissue transcript profiling (2 mice/group) was performed using Affymetrix Mouse Genome 430 2.0. RESULTS: The high-calcium diet with whey protein altered the expression of 129 genes (+/- 1.2 fold). Quantitative RT-PCR analysis confirmed the significant up-regulation of Adrb3 (p = 0.002) and leptin (p = 0.0019) in the high-calcium whey group. Insulin and adipocytokine signaling pathways were enriched among the up-regulated genes and the fatty acid metabolism pathway among the down-regulated genes. CONCLUSIONS: High-calcium diet with whey protein significantly modifies adipose tissue gene expression. These preliminary findings reveal that targets of a high-calcium diet with whey protein include genes for Adrb3 and leptin, and help to explain how the intake of dairy products might attenuate obesity.

High-calcium diet with whey protein attenuates body-weight gain in high-fat-fed C57Bl/6J mice.

An inverse relationship between Ca intake and BMI has been found in several studies. It has been suggested that Ca affects adipocyte metabolism via suppressing 1,25-dihydroxycholecalciferol (1,25(OH)2-D3) and decreases fat absorption. We studied the effect of Ca and milk proteins (whey and casein) on body weight in C57Bl/6J mice. Male mice, age 9 weeks, were divided into three groups (ten mice per group) receiving modified high-fat (60% of energy) diets. Two groups received a high-Ca diet (1.8% calcium carbonate (CaCO3)), with casein or whey protein (18% of energy), and one group received a low-Ca diet (0.4% CaCO3) with casein for 21 weeks. Food intake was measured daily and body weight twice per week. Body fat content (by dual-energy X-ray absorptiometry) of all mice and faecal Ca and fat excretion of seven mice/group were measured twice during the study. Final body weight (44.1 (SEM 1.1) g) and body fat content (41.6 (SEM 0.6) %) were significantly lower (P < 0.05) in the high-Ca whey group than in the low-Ca casein group (48.1 (SEM 0.8) g and 44.9 (SEM 0.8) %). Body weight and body fat content of the high-Ca casein group did not differ significantly from the low-Ca casein group even though serum 1,25(OH)2-D3 levels were significantly lower (P < 0.001) in both high-Ca groups than in the low-Ca casein group. Thus changes in serum 1,25(OH)2-D3 do not seem to affect body weight in this animal model. There was a significant difference in fat excretion between the high-Ca whey and low-Ca casein groups (3.9 (SEM 0.9) % in the high-Ca whey v. 1.4 (SEM 0.2) % in the low-Ca casein group; P < 0.05), which may partly explain the effect on body weight.

Lipoic acid supplementation prevents cyclosporine-induced hypertension and nephrotoxicity in spontaneously hypertensive rats.

BACKGROUND: Cyclosporine (CsA) has significantly improved long-term survival after organ transplantations. Hypertension and nephrotoxicity are common side effects during CsA treatment and are aggravated by high salt intake. OBJECTIVE: To examine whether lipoic acid (LA), a natural antioxidant that scavenges reactive oxygen species and regenerates/recycles endogenous antioxidants, could prevent CsA-induced hypertension and nephrotoxicity. METHODS: Six-week-old spontaneously hypertensive rats (SHR) on a high-sodium diet (NaCl 6%) received CsA [5 mg/kg subcutaneously (s.c.)] alone or in combination with LA (0.5% w/w) for 6 weeks. Blood pressure, arterial functions, and tissue morphology were determined. Immunohistochemistry, quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and high-pressure liquid chromatography were used for kidney and heart samples. RESULTS: CsA induced severe hypertension, cardiac hypertrophy, endothelial dysfunction, and pronounced albuminuria. Histologically, the kidneys showed severe thickening of the media of the afferent arteries with fibrinoid necrosis, perivascular monocyte/macrophage infiltration and nitrotyrosine overexpression. CsA induced the expression of fibrogenic connective tissue growth factor both in the heart and kidneys. The detrimental effects of CsA were associated with upregulation of myocardial atrial natriuretic peptide (ANP) mRNA expression, paradoxical activation of the renin-angiotensin system (RAS), induction of renal reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase, and overexpression of oxidative stress-induced transcription factor NRF2. LA lowered blood pressure, ameliorated cardiac hypertrophy and endothelial dysfunction, and totally normalized albuminuria. In LA-treated rats, renal and cardiac morphologies were indistinguishable from those of SHR controls. CsA-induced myocardial ANP and connective tissue growth factor (CTGF) mRNA overexpression, RAS activation, NADPH oxidase induction, and NRF2 overexpression were prevented by LA. LA induced the mRNA expression of gamma-glutamylcysteine ligase, the rate-limiting enzyme in glutathione synthesis, and markedly increased hepatic cysteine and glutathione concentrations. CONCLUSIONS: Our findings suggest a salutary role for lipoic acid supplementation in the prevention of CsA-induced hypertension and nephrotoxicity, and underscore the importance of increased oxidative stress in the pathogenesis of CsA toxicity.

GSK-3beta inhibitors attenuate the organ injury/dysfunction caused by endotoxemia in the rat.

OBJECTIVE: Serine-threonine protein kinase glycogen synthase kinase (GSK)-3 is involved in regulation of many cell functions, but its role in regulation of inflammatory response is unknown. Here we investigate the effects of GSK-3beta inhibition on organ injury/dysfunction caused by lipopolysaccharide or coadministration of lipopolysaccharide and peptidoglycan in the rat. DESIGN: Prospective, randomized study. SETTING: University-based research laboratory. SUBJECTS: Ninety-nine anesthetized male Wistar rats. INTERVENTIONS: Study 1: Rats received either intravenous Escherichia coli lipopolysaccharide (6 mg/kg) or vehicle (1 mL/kg; saline). Study 2: Rats received either intravenous E. coli lipopolysaccharide (1 mg/kg) and Staphylococcus aureus peptidoglycan (0.3 mg/kg) or vehicle. The potent and selective GSK-3beta inhibitors TDZD-8 (1 mg/kg intravenously), SB216763 (0.6 mg/kg intravenously), and SB415286 (1 mg/kg intravenously) or vehicle (10% dimethyl sulfoxide) was administered 30 mins before lipopolysaccharide or lipopolysaccharide and peptidoglycan. MEASUREMENTS AND MAIN RESULTS: Endotoxemia resulted in increases in the serum levels of creatinine (indicator of renal dysfunction), aspartate aminotransferase, alanine aminotransferase (markers for hepatocellular injury), lipase (indicator of pancreatic injury), and creatine kinase (indicator of neuromuscular injury). Coadministration of lipopolysaccharide and peptidoglycan resulted in hepatocellular injury and renal dysfunction. All GSK-3beta inhibitors attenuated the organ injury/dysfunction caused by lipopolysaccharide or lipopolysaccharide and peptidoglycan. GSK-3beta inhibition reduced the Ser536 phosphorylation of nuclear factor-kappaB subunit p65 and the messenger RNA expression of nuclear factor-kappaB-dependent proinflammatory mediators but had no effect on the nuclear factor-kappaB/DNA binding activity in the lung. GSK-3beta inhibition reduced the increase in nuclear factor-kappaB p65 activity caused by interleukin-1 in human embryonic kidney cells in vitro. CONCLUSIONS: The potent and selective GSK-3beta inhibitors TDZD-8, SB216763, and SB415286 reduced the organ injury/dysfunction caused by lipopolysaccharide or lipopolysaccharide and peptidoglycan in the rat. We propose that GSK-3beta inhibition may be useful in the therapy of the organ injury/dysfunction associated with sepsis, shock, and other diseases associated with local or systemic inflammation.

Magnesium supplementation prevents angiotensin II-induced myocardial damage and CTGF overexpression.

OBJECTIVES AND DESIGN: Magnesium deficiency promotes vasoconstriction and myocardial damage. Recent studies provide evidence that Ang II mobilizes intracellular Mg through AT1 receptor-mediated pathways. We tested the hypothesis of whether magnesium supplementation prevents Ang II-induced myocardial damage and induction of the profibrotic connective tissue growth factor (CTGF). METHODS: Four-week-old double transgenic rats harboring human renin and angiotensinogen genes (dTGR) were given dietary magnesium supplementation (0.6%) for 3 weeks. Control dTGR and normotensive Sprague-Dawley (SD) rats received normal diet (Mg 0.2%). Histopathological, immunohistochemical and mRNA analysis were used to detect the treatment-related effects of dietary magnesium in dTGR. RESULTS: Magnesium (Mg) supplementation decreased blood pressure, ameliorated cardiac hypertrophy, protected against the development of Ang II-induced myocardial damage and increased serum ionized Mg2+ concentration (all variables P < 0.05). There was no difference in serum ionized Mg2+ concentration between dTGR and SD rats. Myocardial connective tissue growth factor (CTGF) mRNA and protein expressions were increased by 300% in dTGR (P < 0.05), especially in areas with myocardial infarctions and vascular inflammation. Magnesium supplementation prevented Ang II-induced myocardial CTGF overexpression (P < 0.05). Magnesium supplementation also improved the therapeutic effects of the calcineurin inhibitor tacrolimus, which produced marked hypomagnesemia when given as monotherapy. CONCLUSION: Our findings suggest a salutary effect for magnesium supplementation in the treatment of Ang II-induced myocardial complications.

High sodium intake increases vascular superoxide formation and promotes atherosclerosis in apolipoprotein E-deficient mice.

Hypertension is a major risk factor for atherosclerosis. We tested the hypothesis whether high salt intake aggravates endothelial dysfunction and promotes atherosclerosis in apolipoprotein E-deficient mice (ApoE(-)/(-) mice) and their littermate controls (C57Bl/6 mice). The role of increased oxidative stress was also examined. A high-salt diet (NaCl 7%) for 12 weeks increased blood pressure and induced cardiac hypertrophy and albuminuria more pronouncedly in ApoE(-)/(-) mice compared with C57Bl/6. Endothelium-dependent vascular relaxation in response to acetylcholine was almost maximally impaired in ApoE(-)/(-) mice during a normal sodium diet. A high-salt diet did not further impair NO-mediated vascular relaxation. A high-salt diet also markedly attenuated endothelium-dependent relaxation in C57Bl/6 mice. Preincubation with the superoxide scavenger Tiron normalized endothelial function almost completely in both mice strains indicating the central role of increased oxidative stress in the pathogenesis. Aortic superoxide production and the extent of atherosclerotic lesions were greater in ApoE(-)/(-) mice on a normal-salt diet compared with C57Bl/6. The high-salt diet increased vascular superoxide formation and promoted atherosclerosis in ApoE(-)/(-) mice. Changes in dietary salt intake did not influence serum lipids in either mouse strains. Our findings suggest a detrimental role for high salt intake in the development of atherosclerosis and underscore the importance of increased oxidative stress in the pathogenesis salt-induced vascular damage.

Entacapone protects from angiotensin II-induced inflammation and renal injury.

OBJECTIVES AND DESIGN: Angiotensin II (Ang II)-induced renal damage is associated with perivascular inflammation and increased oxidative stress. We tested the hypothesis whether entacapone, a catechol-O-methyltransferase (COMT) inhibitor exerting antioxidative and anti-inflammatory properties, protects against the Ang II-induced inflammatory response and end-organ damage. METHODS: Samples from double-transgenic rats harbouring human renin and human angiotensinogen genes (dTGR) and normotensive Sprague-Dawley rats (SD) were assessed by light microscopy, immunohistochemistry, reverse transcriptase-polymerase chain reaction (RT-PCR), and high pressure liquid chromatography. The effects of entacapone treatment for 3 weeks were examined in dTGR and SD. RESULTS: Entacapone completely prevented cardiovascular mortality and decreased albuminuria by 85% in dTGR. Entacapone ameliorated Ang II-induced vascular and glomerular damage, leucocyte infiltration, and intercellular adhesion molecule-1 (ICAM-1) overexpression in the kidneys. Serum 8-isoprostane concentration, as well as renal nitrotyrosine and 8-hydroxydeoxyguanosine expressions, all markers of oxidative stress, were markedly increased in dTGR and normalized by entacapone. Entacapone also decreased p22phox mRNA expression in the kidney. COMT expression was increased by 500% locally in the renal vascular wall in dTGR; however, COMT activity in the whole kidney remained unchanged. Urinary dopamine excretion, a marker of renal dopaminergic tone, was decreased by 50% in untreated dTGR. Even though entacapone decreased renal COMT activity by 40%, the renal dopaminergic tone remained unchanged in entacapone-treated dTGR. CONCLUSION: Our findings suggest that entacapone provides protection against Ang II-induced renal damage through antioxidative and anti-inflammatory mechanisms, rather than by COMT inhibition-induced changes in renal dopaminergic tone.

Resistance to salt-induced hypertension in catechol-O-methyltransferase-gene-disrupted mice.

BACKGROUND: Previous studies have indicated that catechol-O-methyltransferase (COMT) can modulate renal dopaminergic tone. OBJECTIVE: To test the hypothesis that COMT blockade protects from salt-induced hypertension. METHODS: COMT gene-disrupted (-/-) mice and wild-type controls received a high-sodium diet (NaCl 6%) for 3 weeks. Blood pressure and heart rate were recorded by radiotelemetry. Tissue and urine samples were assessed by light microscopy and high-performance liquid chromatography. The effects of nitecapone treatment were also examined. Systolic blood pressure and heart rate during normal sodium diet were similar in COMT (-/-) and wild-type mice. The high-sodium diet increased night-time systolic and diastolic blood pressures in wild-type mice, whereas blood pressure in COMT (-/-) mice remained unaltered. In wild-type mice, the sodium-induced increase in blood pressure was completely normalized by treatment with the COMT inhibitor, nitecapone. At baseline, 24-h urinary excretion of levodopa (L-DOPA), dopamine and noradrenaline was increased by 145, 85 and 74%, respectively, in COMT (-/-) mice compared with wild-type controls. In COMT (-/-) and wild-type mice, a high-sodium diet increased urinary L-DOPA excretion by 405 and 660% (reflected as 102 and 212% increases in dopamine excretion), respectively. The absolute amounts of urinary L-DOPA and dopamine remained 60 and 20% greater in COMT (-/-) mice. The high-sodium diet did not influence renal cortical COMT activity. CONCLUSION: Our findings suggest that COMT deficiency in mice increases the availability of L-DOPA, leading to enhanced dopaminergic tone, which may be associated with resistance to salt-induced hypertension. The findings of the present study also underline the importance of COMT in the regulation of blood pressure, sodium excretion and renal dopaminergic tone.

Cardiovascular and renal effects of cyclooxygenase inhibition in transgenic rats harboring mouse renin-2 gene (TGR[mREN2]27).

The present study examined the role of cyclooxygenase-synthetized prostanoids in the pathogenesis of angiotensin-II-induced inflammatory response and vascular injury in transgenic rats harboring mouse renin-2 gene (mREN2 rats). Five- to six-week-old, heterozygous mREN2 rats received the following drug regimens for 8 weeks: (1) controls; (2) cyclooxygenase-2 inhibitor (MF-tricyclic [3-(3,4-difluorophenyl)-4-(4-(methylsulfonyl) phenyl)-2(5H)-furanone], 14 mg kg(-1) p.o.); (3) cyclooxygenase-1/cyclooxygenase-2 inhibitor (sulindac, 14 mg kg(-1) p.o.); (4) angiotensin II receptor antagonist (losartan 40 mg kg(-1) p.o.); (5) MF-tricyclic + losartan; (6) sulindac + losartan. Normotensive Sprague-Dawley rats served as controls. mREN2 rats developed pronounced hypertension, cardiac hypertrophy, and albuminuria as compared to normotensive Sprague-Dawley controls. mREN2 rats showed pronounced perivascular inflammation and morphological damage in the kidneys and the heart. Both MF-tricyclic and sulindac further increased blood pressure and albuminuria in mREN2 rats. Neither MF-tricyclic nor sulindac were able to prevent angiotensin-II-induced perivascular inflammation and morphological changes in the heart or in the kidneys. Myocardial and renal cyclooxygenase-2 mRNA expressions were decreased in mREN2 rats, whereas no difference was found in cyclooxygenase-1 mRNA expressions. Sulindac increased both cyclooxygenase-1 and cyclooxygenase-2 gene expressions, whereas MF-tricyclic increased only cyclooxygenase-2 gene expressions. Losartan normalized blood pressure, cardiac hypertrophy, albuminuria, inflammatory response and morphological changes in mREN2 rats, both in the presence and absence of cyclooxygenase inhibitors. Our findings indicate that cyclooxygenase does not play a central role in the pathogenesis of angiotensin-II-induced inflammatory response and vascular injury in mREN2 rats.

Lacidipine inhibits adhesion molecule and oxidase expression independent of blood pressure reduction in angiotensin-induced vascular injury.

Dihydropyridines can inhibit gene expression in-vitro and may have a protective vascular effect independent of blood pressure reduction. We tested the hypothesis that lacidipine prevents induction of inducible NO synthase (iNOS), influences leukocyte adhesion and infiltration, inhibits nuclear factor (NF)-kappaB transcription factor activity, and ameliorates end-organ damage in a transgenic rat model of angiotensin (Ang) II--dependent organ sclerosis. We treated rats transgenic for human renin and angiotensinogen (dTGR) from week 4 to 7 with lacidipine (0.3 or 3 mg/kg by gavage). Blood pressure was measured by tail cuff. Organ damage was assessed by histology and immunohistochemistry. Adhesion molecules and cytokines were analyzed by immunohistochemistry. Transcription factors were analyzed by mobility shift assays. Untreated dTGR developed moderate hypertension, cardiac hypertrophy, and severe renal damage with albuminuria. Lacidipine decreased blood pressure slightly at the low dose and substantially at the higher dose. However, both treatments reduced albuminuria and plasma creatinine to the same degree (P<0.05). Intercellular adhesion molecule-1 (ICAM-1) was markedly reduced by lacidipine as well as renal neutrophil and monocyte infiltration. Lacidipine reduced mitogen-activated protein (MAP) kinase phosphorylation and iNOS expression in both cortex and medulla. NF-kappaB and AP-1 were activated in dTGR but reduced by lacidipine. Lacidipine ameliorates Ang II-induced end-organ damage independent of blood pressure lowering, perhaps by inhibiting the MAP kinase pathway and NF-kappaB activation.