Tacrolimus induces glomerular injury via endothelial dysfunction caused by reactive oxygen species and inflammatory change.

BACKGROUND/AIMS: The immunosuppressive drug tacrolimus (FK506) is used clinically to reduce the rejection rate in patients with kidney transplantation; however, the resultant nephrotoxicity remains a serious problem. In the present study we attempted to elucidate the mechanisms of glomerular injury induced by FK506 and the renoprotective effects of the angiotensin II receptor blocker telmisartan. METHODS: Seven-week-old male Wistar rats were divided into three groups: vehicle group, FK506 group, and FK506 + telmisartan group. After 8 weeks, we assessed kidney function and renal morphological changes including oxidative stress. We also assessed the effect of FK506 in human glomerular endothelial cells (hGECs) with regard to reactive oxygen species (ROS). RESULTS: FK506 induced ROS production via activation of NAD(P)H oxidase in the glomeruli. Expression of ICAM mRNA was increased in glomeruli from the FK506 group. These effects resulted in macrophage infiltration into the glomeruli. FK506 directly promoted NAD(P)H oxidase activity and accelerated production of ROS in hGECs. Conversely, cotreatment with telmisartan inhibited both NAD(P)H oxidase activity and production of ROS. CONCLUSION: These findings suggest that glomerular injury resulting from FK506 is caused by oxidative stress mediated by activation of NAD(P)H oxidase and that telmisartan exerts a renoprotective effect via antioxidative activity.

Azelnidipine attenuates glomerular damage in Dahl salt-sensitive rats by suppressing sympathetic nerve activity.

Dihydropyridine-type calcium channel blockers (CCBs) exert potent antihypertensive effects. The CCB azelnidipine decreases heart rate by suppressing sympathetic nerve activity, which affects afferent and efferent arterioles in the glomeruli. We examined whether azelnidipine can improve progressive glomerular injury in comparison with amlodipine by suppressing renal sympathetic nerve activity in Dahl salt-sensitive rats. Glomerular circulation in Dahl salt-sensitive rats was monitored with a charge-coupled device camera before and after administration of amlodipine (0.5 mg kg(-1), bolus injection) or azelnidipine (0.1 mg kg(-1), bolus injection). Systemic sympathetic nerve activity was also compared by analysis of heart rate variability with a telemetry blood pressure monitoring system after crossover administration of amlodipine (1.0 mg kg(-1) per day) and azelnidipine (3.0 mg kg(-1) per day) for 1 week. To investigate renoprotective effects, rats were treated with amlodipine (1.0 mg kg(-1) per day) or azelnidipine (3.0 mg kg(-1) per day) for 3 weeks with or without renal denervation. The efferent arteriole contracted in response to acute amlodipine but not azelnidipine treatment. The low frequency/high frequency ratio, an index of parasympathetic nerve activity, decreased in response to azelnidipine but not amlodipine treatment. In response to chronic treatment, proteinuria and glomerular injury improved to a greater extent with azelnidipine compared with amlodipine. The renoprotective effects of azelnidipine were diminished by renal denervation. Azelnidipine decreased glomerular damage in Dahl salt-sensitive rats to a greater extent than amlodipine. Azelnidipine appeared to decrease intraglomerular pressure by suppressing sympathetic nerve activity.

A novel mutation ApoE2 Kurashiki (R158P) in a patient with lipoprotein glomerulopathy.

Lipoprotein glomerulopathy (LPG) is a rare glomerulopathy caused by lipoprotein thrombi. In almost all cases of LPG, several apolipoprotein (apo) E mutations were reported. Here, we present a case of LPG caused by a novel mutation that we named ApoE2 Kurashiki, which substitutes arginine with proline at apoE codon 158. ApoE2 polymorphism is well known for its relationship to type III hyperlipoproteinemia, and the common apoE2 isoform is encoded by the R158C allele. ApoE2 Kurashiki substitutes at the same codon and cannot be distinguished from common apoE2 by stan-dard apoE genotyping or phenotyping.

Overexpression of klotho protein modulates uninephrectomy-induced compensatory renal hypertrophy by suppressing IGF-I signals.

The klotho gene is highly expressed in the distal convoluted tubule of the kidney, while its encoded protein has many physiological and pathophysiological renal roles. We investigated the effect of klotho protein on physiological compensatory renal hypertrophy after nephrectomy in klotho transgenic (KLTG) mice. Renal hypertrophy was suppressed in KLTG mice compared with wild-type mice, and this was associated with suppression of insulin growth factor-1 (IGF-1) signaling by klotho protein. In vitro, IGF-1 signaling was suppressed in human proximal tubular cells transfected with the klotho plasmid. Our data suggest that klotho modulates compensatory renal hypertrophy after nephrectomy via suppression of the IGF-1 signaling pathway, indicating a novel physiological role for klotho protein in the kidney.

Comparison of combination therapy of olmesartan plus azelnidipine or hydrochlorothiazide on renal and vascular damage in SHR/NDmcr-cp rats.

BACKGROUND: Although the recommended target blood pressure for patients with chronic kidney disease is <130/80 mm Hg, this is difficult to achieve by treatment with an angiotensin receptor blocker alone. Addition of either a calcium channel blocker or a diuretic is suggested as second-line medication; however, which combination is most beneficial for target-organ protection remains unknown. METHODS: SHR/NDmcr-cp rats were administered no medications (control) or low-dose olmesartan for 2 weeks and then either olmesartan at an increased dose, azelnidipine, or the hydrochlorothiazide for 3 weeks. We assessed oxidative stress in the kidney and aorta, and endothelial function. RESULTS: Urinary protein excretion was lower in all treated rats than in control rats. Oxidative stress caused by activation of NAD(P)H oxidase was observed in the glomeruli and aorta of control rats and was significantly suppressed in the olmesartan/azelnidipine (Olm/Azl) groups. Combination therapy with olmesartan and hydrochlorothiazide (Olm/HCTZ) however failed to suppress oxidative stress. The Olm/Azl groups maintained the endothelial surface layer in the glomeruli and protected endothelial function in the aorta. CONCLUSION: In an animal model of metabolic syndrome, a combination of Olm/Azl is superior to a combination of Olm/HCTZ in terms of prevention of glomerular and vascular injuries.

Mitochondrial damage-induced impairment of angiogenesis in the aging rat kidney.

Decreased expression of vascular endothelial growth factor (VEGF) in the renal tubules is thought to cause progressive loss of the renal microvasculature with age. Mitochondrial dysfunction may be a principal phenomenon underlying the process of aging. The relation between VEGF expression and mitochondrial dysfunction in aging is not fully understood. We hypothesized that mitochondrial dysfunction blocks VEGF expression and contributes to impaired angiogenesis in the aging kidney. The aim of this study was to assess the role of mitochondria in VEGF expression in the aging rat kidney. We evaluated the accumulation of 8-hydroxy-2'-deoxyguanosine in mitochondrial DNA, as well as mitochondrial dysfunction, as assessed by electron microscopy of mitochondrial structure and histochemical staining for respiratory chain complex IV, in aging rat kidney. An increase in hypoxic area and a decrease in peritubular capillaries were detected in the cortex of aging rat kidneys; however, upregulation of VEGF expression was not observed. The expression of VEGF in proximal tubular epithelial cells in response to hypoxia was suppressed by the mitochondrial electron transfer inhibitor myxothiazol. Mitochondrial DNA-deficient cells also failed to upregulate VEGF expression under hypoxic conditions. These results indicate that impairment of VEGF upregulation, possibly as a result of mitochondrial dysfunction, contributes to impaired angiogenesis, which in turn leads to renal injury in the aging rat kidney.

Renal denervation reduces glomerular injury by suppressing NAD(P)H oxidase activity in Dahl salt-sensitive rats.

BACKGROUND: Renal sympathetic nerve activity has important effects on renal function in chronic kidney disease. Recent studies indicated that beta agonists directly stimulate NAD(P)H oxidase in endothelial cells. Therefore, we investigated whether renal denervation protects renal function through an anti-oxidative effect. METHODS: The right kidney was removed from Dahl salt-sensitive hypertensive rats. Two weeks later, the rats underwent either left renal denervation (Nx-RDNx; n = 10) or a sham operation (Nx-Sham; n = 10). After a further 6 weeks, kidney function and renal tissue were assessed. In this ex vivo study, using isolated glomeruli from Sprague-Dawley rats, the direct effects of catecholamine on NAD(P)H oxidase activity were assessed. RESULTS: After the Nx-RDNx or Nx-Sham surgery, urinary albumin excretion and the histologic glomerular sclerosis index were lower in the Nx-RDNx group than in the Nx-Sham group. Fluorescence staining for reactive oxygen species in isolated glomeruli was significantly weaker in the Nx-RDNx group. A lucigenin assay of NAD(P)H oxidase activity in isolated glomeruli indicated that renal denervation may have caused the reduction in reactive oxygen species through suppression of the activity of NAD(P)H oxidase. The levels of mRNA for NAD(P)H oxidase components and the levels of rac1 were higher in glomeruli from the Nx-Sham group than from the Nx-RDNx group. In this ex vivo study, although the NAD(P)H oxidase activity did not change with administration of either the alpha- or beta2-agonist, it increased with the beta1-agonist. CONCLUSIONS: Renal sympathetic denervation helps to protect against glomerular sclerosis, possibly by suppressing NAD(P)H oxidase activity, thereby decreasing glomerular reactive oxygen species.

In vivo visualization of glomerular microcirculation and hyperfiltration in streptozotocin-induced diabetic rats.

OBJECTIVES: Knowledge of glomerular structural and hemodynamic changes in vivo is still limited under diabetic conditions. In this study, we examined the alterations in glomerular structure and permeability of macromolecules and the effects of telmisartan using a confocal laser microscope. METHODS: Diabetes was induced by injecting streptozotocin. After 4 and 8 weeks, the filtration and permeability of differently sized compounds across the glomerular capillaries were visualized using a confocal laser microscope by injecting 500-kilodalton and 40-kilodalton dextran. At 7 weeks, some diabetic rats were treated with telmisartan for 1 week. The permeation of the 40-kilodalton dextran across the glomerular capillaries into Bowman's space was quantified. Glomerular volume, diameters of the afferent and efferent arterioles, and glomerular permeability were compared. RESULTS: Glomerular volume was significantly increased in the diabetic rats, and there was heterogeneity in the glomerular volumes. The diameter ratio of the afferent to efferent arterioles significantly increased, and there was increased glomerular permeability in the diabetic rats compared with the control rats. Telmisartan treatment reduced glomerular permeability without affecting glomerular volume. CONCLUSIONS: These data showed that glomerular hyperfiltration started from the early phase of diabetes, accompanied by dilatation of afferent arterioles and glomerular hypertrophy.

Reactive oxygen species mediate compensatory glomerular hypertrophy in rat uninephrectomized kidney.

Hyperfiltration in glomeruli is the most common pathway to progressive renal dysfunction. Moreover, reduction of renal mass by unilateral nephrectomy results in an immediate increase in glomerular flow to the remnant kidney, followed by compensatory glomerular hypertrophy. Reactive oxygen species (ROS) are involved in renal hypertrophic responses; however, the role of ROS in compensatory glomerular hypertrophy remains unclear. Therefore, this role was investigated in the present study. Wistar rats were randomly placed into two groups: uninephrectomized rats (Nx) and uninephrectomized rats treated with tempol (Nx + TP). The glomerular volume increased in the Nx 1 week after surgery, but was significantly suppressed in the Nx + TP. Levels of phospho-Akt and phospho-ribosomal protein S6, which are critical for cell growth and hypertrophy, were markedly increased in the glomeruli of the Nx, while tempol treatment almost abolished the activation of these proteins. These results suggest that ROS have important roles in compensatory hypertrophy in glomeruli.

Oral adsorbent AST-120 ameliorates endothelial dysfunction independent of renal function in rats with subtotal nephrectomy.

It is important to consider a strategy to halt the development of cardiovascular disease (CVD) in patients with chronic kidney disease (CKD). Oral adsorbent AST-120 retards deterioration in renal function, reducing indoxyl sulfate (IS) accumulation. The aim of this study was to determine whether AST-120 improves endothelial dysfunction by reducing oxidative/nitrative stress in a rat-CKD model. Subtotally nephrectomized (Nx) rats aged 17 weeks were divided into two groups: control rats and rats orally treated with AST-120. Two weeks after initiation of AST-120, serum and urinary IS levels, renal histological scores and endothelium-dependent vascular responses (EDVRs) in the aorta were investigated. EDVR in 5-h incubation with 250 microg ml(-1) IS was also examined in normal rat aortas. Nitrotyrosine content, mRNA expression of p47phox, a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase component, and expression and phosphorylation (serine-1177) of endothelial nitric oxide synthase (eNOS) in the aorta were examined in untreated and treated Nx rats. At the end of treatment, renal function and histological scores were not different in the two groups. AST-120 prevented the elevation of serum IS level in Nx rats, reducing urinary IS excretion, and ameliorated decreased EDVR in Nx rats. Incubation with IS tended to reduce EDVR in normal aortas, albeit insignificantly. AST-120 also suppressed nitrotyrosine accumulation and inhibited p47phox expression in Nx rats. The eNOS expression and phosphorylation were similar in the two groups. In conclusion, AST-120 ameliorated endothelial dysfunction and alleviated oxidative/nitrative stress in the aorta through reduced accumulation of IS, independent of renal function, in a rat CKD model.

High dietary protein intake induces endothelial dysfunction in uninephrectomized rats.

High dietary protein (HP) intake is a risk factor for chronic kidney disease (CKD). HP intake is associated with the development of albuminuria and glomerulosclerosis in uninephrectomized rats. In such rats, we investigated whether HP intake induces endothelial dysfunction. Male Wistar rats were divided into sham-operated rats fed a standard-protein diet, sham-operated rats fed a high-protein diet, uninephrectomized rats fed a standard-protein diet (NxSP) and uninephrectomized rats fed a high-protein diet (NxHP) (n=8 each). One week after treatment, endothelial function and urinary albumin excretion (UAE) were measured. Protein expression, phosphorylation at serine residue 1177 and uncoupling of endothelial nitric oxide synthase (eNOS), and mRNA expression of NADPH oxidase components were assessed in the aorta. NxHP rats showed hypertriglyceridemia and modest hyperhomocysteinemia. Endothelial function was significantly lower, and UAE was significantly higher in NxHP rats compared with the other groups (P<0.01 each), although there was no difference in creatinine clearance between NxSP and NxHP rats. Expression levels, phosphorylation and the dimer/monomer ratio of eNOS did not differ among the four groups. HP intake did not modify p22phox and p47phox expression levels in uninephrectomized rats. In conclusion, HP intake induced endothelial dysfunction and enhanced albuminuria in uninephrectomized rats, inde-pendent of renal function, suggesting that HP intake may cause the development of cardiovascular disease associated with CKD.

Combination therapy based on the angiotensin receptor blocker olmesartan for vascular protection in spontaneously hypertensive rats.

For hypertension, combination therapies are recommended to achieve a low target blood pressure. In this study, the efficacy of combination therapies for preventing organ damage was investigated in spontaneously hypertensive rats (SHR). Twenty-week-old male SHR were orally administered olmesartan (Olm) (5 mg/kg/day) for the first 4 weeks. Subsequently, rats were randomly divided into 5 groups and administered add-on drugs for another 4 weeks as follows: Olm+Olm (5 mg/kg/day), Olm+azelnidipine (Aze) (30 mg/kg/day), Olm+temocapril (Tem) (10 mg/kg/day), Olm+atenolol (Ate) (5 mg/kg/day), Olm+hydrochlorothiazide (HCTZ) (5 mg/kg/day). Blood pressure and heart rate were measured at weeks 0, 4 and 8 by the tail-cuff method. Heart and kidney weights were determined, and endothelial function was assessed by evaluating the dilator response to acetylcholine. In comparison to untreated control SHR, a significant reduction in systolic blood pressure was observed at weeks 4 and 8 in all groups (p<0.05), while heart rate was significantly reduced at week 8 in only the Olm+Aze and Olm+Ate groups (p<0.05). In all groups, heart but not kidney weight was significantly decreased (p<0.05), and endothelial function was significantly improved (p<0.05) compared to the control SHR. In the Olm+Olm, Olm+Tem and Olm+Aze groups, endothelial function was significantly improved as compared to the other treatment groups (p<0.05). Thus, when using an angiotensin receptor blocker as a first-line therapy, an antihypertensive in the form of an angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, or calcium channel blocker, such as azelnidipine, should be used as a second-line drug to protect against vascular damage.

Pioglitazone enhances the antihypertensive and renoprotective effects of candesartan in Zucker obese rats fed a high-protein diet.

The metabolic syndrome is a risk factor for the development of chronic kidney disease. Angiotensin II type 1 receptor blockers (ARBs) and thiazolidinediones (TZDs) provide renovascular protection, probably in the metabolic syndrome. However, the effect of both agents administered together in patients with metabolic syndrome remains to be determined. The aim of this study was to assess the effects of ARB plus TZD combination therapy in Zucker obese rats fed a high-protein diet, an animal model of metabolic syndrome and renal injury. Zucker obese rats were fed a high-protein diet (OHP; n=6), a high-protein diet containing candesartan, an ARB (OHP+C; n=6), or a high-protein diet containing both candesartan and pioglitazone (OHP+CP; n=6) for 12 weeks. Systolic blood pressure and urinary protein excretion were measured throughout the study, and renal histology and immunohistochemistry were assessed at 12 weeks. OHP rats developed hypertension (157+/-4 mmHg) and proteinuria (178+/-44 mg/d), and these conditions were significantly ameliorated by candesartan (to 143+/-3 mmHg and 84+/-25 mg/d, respectively). Pioglitazone enhanced the antihypertensive and anti-proteinuric effects of candesartan (121+/-3 mmHg, 16+/-8 mg/d, respectively). Histologically, candesartan ameliorated glomerulosclerosis, podocyte injury, interstitial fibrosis and monocyte/macrophage infiltration into the tubulointerstitium in the kidneys of OHP rats. Pioglitazone abrogated residual interstitial fibrosis in the kidneys of OHP+C rats. Our results suggested that pioglitazone augmented the antihypertensive, anti-proteinuric and possibly renal anti-fibrotic actions of candesartan in Zucker obese rats fed a high-protein diet. The combination therapy of ARB and TZD may protect against renal injury in patients with metabolic syndrome.

Olmesartan ameliorates progressive glomerular injury in subtotal nephrectomized rats through suppression of superoxide production.

Angiotensin type 1 receptor blockers are more effective than other antihypertensive agents in slowing the progression of renal disease. Angiotensin II (Ang II) induces production of NAD(P)H oxidase-dependent superoxide in vascular and mesangial cells, but the direct role of Ang II in glomerular superoxide production remains unknown. Here we examined the effect of Ang II on superoxide production both ex vivo and in vivo. Ang II increased superoxide generation in isolated normal glomeruli in a dose-dependent manner, and co-incubation with olmesartan, an angiotensin type 1 receptor blocker, suppressed such increase. Subtotal nephrectomized rats (Nx, n=8) showed impaired renal function, increased glomerular sclerosis, and significantly high superoxide production in glomeruli. These changes were inhibited in olmesartan-treated (n=8), but not hydralazine-treated (n=8) Nx rats. Oxidative stress and nitrosative stress were observed in Nx glomeruli, as evidenced by increased levels of carbonyl protein and nitrotyrosine formation, respectively. These changes were inhibited by 8-week treatment with olmesartan. The apoptosis observed in Nx glomeruli was also suppressed by olmesartan. Superoxide generation in Nx glomeruli was blocked by an NAD(P)H oxidase inhibitor, diphenylene iodinium. The mRNA expression levels of two NAD(P)H oxidase subunits were increased in Nx, and olmesartan significantly reduced the mRNA expression levels. These results indicate that Ang II directly induced superoxide production through activation of NAD(P)H oxidase, and olmesartan would inhibit superoxide production and oxidative stress independent of its blood pressure-lowering effect. These findings support the notion that superoxide plays a primary role in glomerular injury in chronic kidney disease.

Blockade of serotonin 2A receptor improves glomerular endothelial function in rats with streptozotocin-induced diabetic nephropathy.

BACKGROUND: Serotonin (5-HT) is involved in vascular inflammation and atherosclerogenesis. Serum 5-HT concentrations are elevated in diabetes, and 5-HT is involved in diabetic vasculopathies. Sarpogrelate hydrochloride, a 5-HT2A receptor antagonist, has renoprotective effects, but its effect in diabetic nephropathy is not elucidated. The aim of this study was to examine the effects of sarpogrelate on endothelial dysfunction in rats with streptozotocin (STZ)-induced diabetes. METHODS: Rats with STZ-induced diabetes were either untreated or treated with sarpogrelate (30 mg/kg P.O.) for 8 weeks. At the end of the experiment, we measured urinary albumin excretion, serum adiponectin concentration and platelet-derived microparticles. Intraglomerular coagulation was detected by immunostaining for platelets. Production of renal reactive oxygen species (ROS) and nitric oxide (NO) was investigated by confocal laser microscopy and used as an index of glomerular endothelial dysfunction. RESULTS: Diabetic nephropathy was associated with enhanced production of ROS and diminished bioavailable NO in the glomeruli. Treatment with sarpogrelate improved ROS/NO imbalance in glomeruli, suppressed platelet aggregation in glomeruli, reduced platelet-derived microparticles, increased serum adiponectin level and reduced the level of albuminuria, compared with non-treated diabetic rats. CONCLUSIONS: Our results indicate that sarpogrelate improves endothelial function in rats with STZ-induced diabetes through a reduction of glomerular platelet activation and an increase in serum adiponectin concentrations and suggest that sarpogrelate is potentially useful for the treatment of diabetic nephropathy.

Inhibition of experimental abdominal aortic aneurysm progression by nifedipine.

Agents to inhibit the renin-angiotensin system have been reported to suppress the progression of abdominal aortic aneurysm (AAA). However, the effects of calcium channel blockers (CCBs) are still unclear in terms of the inhibition of the progression of AAA. Recently, several effects of CCBs beyond those associated with blood pressure lowering have attracted much interest. In this study, we examined the effects of nifedipine on AAA progression. AAA was induced in rats by transient aortic perfusion with elastase. Then, nifedipine (10 mg/kg/day) and saline (control) were administered to rats by osmotic mini-pump. At 2 and 4 weeks, the size of the AAA, blood pressure and heart rate were measured. Then, to further explore the mechanisms of the progression of AAA, we used human vascular smooth muscle cells (VSMCs). Especially, we focused on NF-kappaB and matrix metalloproteinase-9 (MMP-9). Treatment with nifedipine resulted in a significant inhibition of the progression of AAA such as aneurismal dilation at 14 and 28 days compared to the control (week 2: control, 2.98+/-0.71 mm; nifedipine, 2.37+/-0.64 mm; p<0.05 and week 4: control, 3.28+/-0.98 mm; nifedipine, 2.41+/-0.17 mm; p<0.05). Neither nifedipine nor saline changed blood pressure and heart rate, significantly. Nifedipine (1 microM) significantly suppressed angiotensin II-induced (10(-6) M) NF-kappaB activity in VSMCs by reporter assay (p<0.01). Furthermore, nifedipine (1 microM) inhibited MMP-9 protein expression and activity. Saline did not show such inhibitory effects. Taken together, these results indicated that nifedipine inhibits the progression of experimental AAA possibly through suppression of NF-kappaB and MMP-9 activity, leading to protective effects against AAA beyond those associated with blood pressure lowering.

Marked regression of liver metastasis by combined therapy of ultrasound-mediated NF kappaB-decoy transfer and transportal injection of paclitaxel, in mouse.

Nuclear factor-kappaB (NF kappaB) plays a pivotal role in cancer progression. In this study, we developed a decoy cis-element oligo-deoxyribonucleic acid against NF kappaB-binding site (NF kappaB-decoy), which effectively inhibits NF kappaB activity, and tested the effect of combined therapy comprising local transfection of NF kappaB-decoy into the liver and transportal injection of paclitaxel on cancer growth and metastasis using an orthotopic murine model of colon cancer liver metastasis. For NF kappaB-decoy transfection, we employed a novel approach using ultrasound exposure with an echocardiographic contrast agent, Optison. We examined the influence of NF kappaB-decoy transfer on susceptibility to paclitaxel in cancer cells and the mechanism involved using several in vitro analysis systems. We then studied the in vivo effect of combined NF kappaB-decoy transfer and paclitaxel in preventing cancer progression using a murine model of liver metastasis created by splenic injection of a human colon cancer cell line, HT29. In vitro experiments, including MTT-assay, fluorescence-activated cell sorter and cDNA array analysis, revealed that NF kappaB-decoy transfer significantly increased the susceptibility of cancer cells to paclitaxel, and that decreased expression of anti-apoptotic genes along with increased expression of genes relevant to the apoptosis-promotor may be involved. In vivo experiments showed that local transfection of NF kappaB-decoy into the liver followed by portal injection of paclitaxel effectively induced cancer cell apoptosis in the liver metastasis, and significantly prolonged animal survival compared to controls, without notable side effects. In conclusion, a combination of local NF kappaB-decoy transfer into the liver and transportal injection of paclitaxel may be a safe and effective new therapy for liver metastasis.

Olmesartan ameliorates renovascular injury and oxidative stress in Zucker obese rats enhanced by dietary protein.

BACKGROUND: The metabolic syndrome is a risk factor for the development of renal and vascular complications. Dietary protein intake aggravates renal injury in Zucker obese rats, a model of the metabolic syndrome. This study investigated whether dietary protein intake enhances renal and vascular injuries by oxidative stress, and assessed effects of olmesartan, an angiotensin II type 1 receptor blocker, in this model. METHODS: Zucker obese rats were fed either a standard protein diet, high protein diet (OHP), or high protein diet containing olmesartan or hydralazine for 12 weeks. We examined the glomerulosclerosis score, endothelium-dependent relaxation response in the aorta, 4-hydroxy-2-nonenal (HNE) contents in the kidney and aorta, and mRNA expression of NAD(P)H oxidase components (p22phox and p47phox) in the renal cortex. RESULTS: The OHP rats developed proteinuria, glomerulosclerosis, and endothelial dysfunction. Olmesartan prevented the development of all these damages in OHP rats, whereas hydralazine improved only glomerulosclerosis. The high protein diet also augmented HNE accumulation in glomeruli, renal arteries, and aortas, and increased the mRNA expressions of p22phox and p47phox in the renal cortex in obese rats. Olmesartan, but not hydralazine, inhibited all these changes. CONCLUSIONS: These results suggested that increased dietary protein intake exacerbates renal and vascular injuries, and augments oxidative stress in a rat model of the metabolic syndrome. Olmesartan ameliorated these injuries, presumably through its antioxidative effects, whereas hydralazine improved only glomerulosclerosis through its antihypertensive action. Dietary protein-enhanced injuries in the metabolic syndrome may be associated with hypercholesterolemia and the activated renin-angiotensin system.

Pioglitazone ameliorates endothelial dysfunction in obese rats with nephropathy.

Endothelial dysfunction is a key event in the development of renovascular complications in the metabolic syndrome. The aim of this study was to elucidate the pathogenetic mechanisms involved in renovascular injuries in the Zucker obese rat, a model of the metabolic syndrome, and to examine the therapeutic effects of pioglitazone, a thiazolidinedione. Obese rats fed high-protein diet (OHP) for 12 weeks exhibited nephropathy and endothelial dysfunction, which were improved by pioglitazone. Accumulation of nitrotyrosine, a tracer of nitrative stress, was increased in aorta of the OHP group. The mRNA expressions of NADPH oxidase components and inducible nitric oxide synthase in the aorta were enhanced in the OHP group. Pioglitazone reduced nitrotyrosine in the aorta of the OHP group, inhibiting the augmented expression levels of both. These results suggest that nitrative stress could cause endothelial dysfunction in the rat model of metabolic syndrome with nephropathy, and that pioglitazone ameliorates these injuries, presumably by reducing nitrative stress.