Diagnosis of histological gastritis based on the Kyoto classification of gastritis in Japanese subjects - including evaluation of aging and sex difference of histological gastritis.

OBJECTIVES: The Kyoto classification of gastritis was established for diagnosing Helicobacter pylori (H. pylori) infection via endoscopic findings. We investigated the role of the Kyoto classification of gastritis in the diagnosis of H. pylori infection and histological gastritis in Japanese individuals. Moreover, the histological findings of gastritis in H. pylori infection were examined based on age and sex differences. METHODS: We selected 561 patients aged 20-79 years who underwent gastroduodenal endoscopy at our hospital between 2010 and 2018. Endoscopic biopsy specimens from the antrum and corpus were used to investigate H. pylori infection and histology. Endoscopic findings were based on the Kyoto classification of gastritis, and histological findings were based on the updated Sydney System. RESULTS: Endoscopic findings based on the Kyoto classification of gastritis (H. pylori positive, 303 patients; H. pylori negative, 258 patients, based on endoscopic findings) had 98.7% sensitivity and 98.4% specificity for histological gastritis. In addition, endoscopic findings in the three age groups (20-39, 40-59, and 60-79 years) had high sensitivity and specificity. Atrophy and intestinal metaplasia were found only in the H. pylori-positive group and progressed with age. Histological inflammation of pyloric mucosa in the younger age group of H. pylori-positive patients was significantly higher than that in the elderly group. Significant inflammation was observed in young women. CONCLUSIONS: The Kyoto classification of gastritis can not only diagnose H. pylori infection but also detect histological gastritis. Histological gastritis has varying characteristics of inflammation, atrophy, and intestinal metaplasia, depending on age and sex.

Inflammatory Cell Numbers in the Stomach of Japanese Subjects with Endoscopically Normal Mucosa without Helicobacter pylori Infection.

INTRODUCTION: Since inflammatory cells, such as lymphocytes and plasma cells, normally inhabit the stomach, the border between normal and mild inflammation is difficult to visually determine using the updated Sydney system scale of gastritis. Additionally, eosinophils in the gastric mucosa must be counted to diagnose eosinophilic gastritis. We aimed to determine the normal number of inflammatory cells in patients with endoscopically normal mucosa and without Helicobacter pylori infections. METHODS: We assessed patients aged 20-79 years, who had undergone upper gastrointestinal endoscopy at Kawasaki Medical School Hospital between January 2010 and December 2014. Inflammatory cells were counted in 1,000 µm2 fields of pyloric and fundic gland mucosal biopsy specimens. We finally included 325 (male, n = 141; female, n = 184; average age = 49.3 years) patients without inflammation who had H. pylori-negative endoscopic results and negative histological findings interpreted based on the updated Sydney System and the Kyoto classification of gastritis. RESULTS: The average numbers of nucleated cells were 83.3 ± 14.2 and 65.4 ± 12.6/mm2 in the pyloric and fundic gland mucosae, respectively. Inflammatory cells were significantly more abundant in the pyloric mucosa than in the fundic gland mucosa (p < 0.05). Age and sex distribution did not significantly differ. Eosinophils were absent or scanty in the gastric mucosae of both glands in all patients. CONCLUSION: We determined the absolute values of inflammatory cells, including eosinophils, in normal mucosae of pyloric and fundic glands. These findings could be important in defining gastric mucosal inflammation, including eosinophilic gastritis diagnosis.

Acute improvement of endothelial functions after oral ingestion of isohumulones, bitter components of beer.

Isohumulones, principal components of the bitter taste of beers, have antioxidant capacity. We studied i) the effects of oral ingestion of isomerized hop extract (IHE) on the endothelial functions in smokers as well as non-smokers and ii) the effects of IHE on cultured endothelial cells in high oxidative stress state. Twelve cigarette smokers and eleven non-smokers ingested IHE and placebo in a randomized crossover design. Flow-mediated vasodilatation (FMD) was measured using ultrasonography. We also studied the effects of isohumulones on i) the cell viability under hypoxia and ii) the levels of angiotensin II (AT-II)-induced reactive oxygen species (ROS) in the cultured human aortic endothelial cells (HAECs). At baseline, the FMDs of the smokers were significantly lower than those of the non-smokers. The FMDs increased significantly after 30 min and 120 min of IHE ingestion in both the smokers and the non-smokers. IHE protected the HAECs from hypoxia-induced cell death as assessed by cell viability. IHE also reduced the AT-II-induced intracellular ROS level. Oral ingestion of IHE appears to exert acute beneficial effects on the endothelial functions in both the smokers and non-smokers, and the in vitro experiments using HAECs suggested that the effect be through reducing intracellular oxidative stress.

Prevalence of gastroesophageal reflux disease symptoms and effects of esomeprazole on the quality of life related to reflux and dyspepsia in patients on maintenance hemodialysis.

BACKGROUND: The prevalence of gastroesophageal reflux disease (GERD) symptoms has not been investigated in patients on maintenance hemodialysis in Japan, and few studies have reported the effect of proton pump inhibitors (PPIs) in hemodialysis patients with GERD symptoms. Here, we investigated the prevalence of GERD symptoms and the effects of the PPI esomeprazole on the quality of life related to reflux and dyspepsia in patients on maintenance hemodialysis. METHODS: This was a cross-sectional/cohort study of hemodialysis outpatients implemented in 10 Japanese medical facilities from October 2012 to March 2014. The trial was registered in the UMIN Clinical Trial Registry (UMIN000009124). RESULTS: Forty-one of 385 patients (11%) reported GERD symptoms on the Global Overall Symptom (GOS) questionnaire. Multivariate logistic regression analysis identified the independent prognostic factors for GERD symptoms as a history of gastric ulcer and use of sevelamer hydrochloride or calcium polystyrene sulfonate. Participants with GERD symptoms completed the Quality of Life in Reflux and Dyspepsia, Japanese version (QOLRAD-J) questionnaire and were assigned to receive 4-week esomeprazole treatment (20 mg/day). This PPI therapy significantly improved all QOLRAD-J domains in the full analysis set (n = 28) and improved the GERD symptoms listed in the GOS questionnaire. Significantly impaired disease-specific quality of life (QOL) in the QOLRAD-J domains was observed in 44.4-74.1% of patients who had symptoms before treatment. The mean GOS and QOLRAD-J scores correlated significantly. CONCLUSION: Therapy with 20 mg/day esomeprazole appears to be efficacious for improving disease-specific QOL and GERD symptoms in Japanese patients on maintenance hemodialysis.

Relationship between vascular function indexes, renal arteriolosclerosis, and renal clinical outcomes in chronic kidney disease.

AIM: Hypertension contributes critically to the development of renal arteriolosclerosis in chronic kidney disease (CKD), but the impact of vascular function indexes including central blood pressure on renal arteriolosclerosis has not been investigated. We determined whether vascular function indexes were related to renal arteriolosclerosis and renal clinical outcomes in CKD. METHODS: This cross-sectional study was implemented in our hospital. Subjects were in-patients with CKD aged ≥20 years who underwent a renal biopsy. Vascular function indexes included central systolic blood pressure (SBP), cardio-ankle vascular index (CAVI), and renal resistive index. Central SBP was measured non-invasively using an automated device. Arteriolosclerosis was assessed histologically. Renal clinical outcomes included estimated glomerular filtration rate using serum creatinine (eGFRcreat) or cystatin C (eGFRcys), and the urinary albumin-creatinine ratio. RESULTS: Among vascular function indexes, central SBP was weakly correlated with renal arteriolosclerosis (n = 55). Renal arteriolosclerosis was increased in hypertensive or hyperuricaemic patients, and negatively correlated with serum high-density lipoprotein (HDL) cholesterol and eGFRcys, which were independent risk factors for renal arteriolosclerosis in a stepwise multivariate regression analysis. Of the vascular function indexes, CAVI showed the strongest correlation with all renal clinical outcomes. Central SBP was correlated with only urinary albumin-creatinine ratio, while renal resistive index was correlated with eGFRcreat and urinary albumin-creatinine ratio. CONCLUSION: Decreased serum HDL cholesterol was independently and most closely associated with renal arteriolosclerosis. Of the vascular function indexes, CAVI had the greatest impact on renal clinical outcomes, although it was not associated with renal arteriolosclerosis.

Angiostatin production increases in response to decreased nitric oxide in aging rat kidney.

The development of interstitial fibrosis occurs with aging. Impaired angiogenesis, associated with progressive loss of the renal microvasculature, is thought to be a cause of age-related nephropathy. However, the mechanism of capillary loss in aging kidney has not been fully elucidated. Angiostatin is a kringle-containing fragment of plasminogen and is a potent inhibitor of angiogenesis in vivo. Whether angiostatin generation is increased in the aging kidney has not been investigated. We examined 4, 10, 16, and 24-month-old Sprague-Dawley rats for angiostatin production and found that angiostatin generation was increased in aged rats. The protein expression and the activity of cathepsin D-the enzyme for angiostatin production--were increased in aged rats. In the aging kidney, nitric oxide (NO) availability is decreased. To investigate the role of NO in angiostatin production, human umbilical vein endothelial cells were treated with L-NG-nitroarginine methyl ester (L-NAME). L-NAME-treated cells showed increased cathepsin D activity and angiostatin production. For in vivo experiments, 16- to 18-month-old rats were treated with L-NAME or molsidomine for 3 months. Angiostatin production was increased in L-NAME-treated kidney, accompanied by increased cathepsin D activity. In contrast, angiostatin production was decreased in molsidomine-treated kidney, accompanied by decreased cathepsin D activity. In conclusion, angiostatin generation by cathepsin D was increased in the aging rat kidney. Decreased NO production activated cathepsin D activity. Increased angiostatin production may be related to capillary loss and interstitial damage in the aging rat kidney.

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.

Associations between lifestyle behaviour changes and the optimal well-being of middle-aged Japanese individuals.

BACKGROUND: Psychological well-being has been associated with reduced mortality rates in both healthy and diseased populations. However, there is considerably less evidence on the effect of lifestyle behaviours on positive health outcomes such as well-being. This study examines the association between lifestyle behaviours and optimal well-being. METHODS: From a total of 4324 Japanese individuals who participated in an annual health check-up in 2017, this study recruited 2295 participants (mean age: 49.3 ± 8.4 years; female: 54.3%) without a history of cerebrovascular, cardiovascular, or chronic renal disease and not on medication for hypertension, diabetes, or dyslipidaemia. The World Health Organization-Five Well-Being Index (WHO-5) scores were compared to self-reported scores on each of the following items: dietary habits, physical activity, smoking, alcohol consumption, and sleep quality. Logistic regression analysis was used to examine the association between optimal well-being (the top quartile of WHO-5 scores) and individual lifestyle behaviours. The association between change in dietary habits and physical activity from 2016 to 2017 and optimal well-being was also investigated. RESULTS: Good dietary habits and regular physical activity were associated with higher raw WHO-5 scores and were positively associated with optimal well-being after adjusting for age, sex, body mass index (BMI), and sleep quality. Raw WHO-5 scores were significantly higher in those who maintained good dietary and physical activity behaviours than in those who did not. Furthermore, maintaining regular physical activity for two years was positively associated with optimal well-being, after adjusting for age, sex, BMI, and sleep quality. CONCLUSION: These results demonstrate that not only currently practising good dietary and physical activity behaviours but also maintaining such behaviours over time is associated with optimal well-being. Maintaining good lifestyle behaviours, particularly regarding physical activity, could potentially improve people's well-being.

Azelnidipine exerts renoprotective effects by improvement of renal microcirculation in angiotensin II infusion rats.

BACKGROUND: Hypoxia-induced tubulointerstitial injury caused by loss of peritubular capillary (PTC) blood flow may be associated with progressive renal disease. Therefore, the maintenance of blood flow in PTCs may protect against loss of renal function. A long-acting calcium channel blocker, azelnidipine, has been shown to be useful in the treatment of progressive renal disease. However, its mechanism of action remains unclear. The aim of the present study was to elucidate whether azelnidipine maintains PTC blood flow and to compare it to nifedipine in its ability to improve tubulointerstitial injury caused by angiotensin II (AII) infusion in rats. METHODS: PTC blood flow was initially monitored using a pencil-lens interval microscope before and after intravenous AII (30 ng/kg/min) infusion with or without azelnidipine (10 microg/kg/min). Next, Wistar rats were treated with chronic infusion of AII (500 ng/kg/min) via an osmotic minipump with or without azelnidipine (3 mg/kg/day, orally) or nifedipine (60 mg/kg/day, orally) for 14 days, and tubulointerstitial damage (PTC loss, interstitial fibrosis, tubular atrophy) was examined. RESULTS: PTC blood flow was reduced after AII infusion but improved after a bolus injection of azelnidipine. Tubulointerstitial damage observed in chronically AII-treated kidneys was associated with hypoxic conditions, as indicated by the measurement of hypoxia biomarkers (intracellular hypoxyprobe-1 adducts). These tubulointerstitial injuries in AII-infused rats were more effectively reduced by azelnidipine than by nifedipine. The area showing hypoxic conditions in the kidney was also more reduced with azelnidipine than nifedipine treatment. CONCLUSIONS: Azelnidipine may increase PTC blood flow and improve renal hypoxia and tubulointerstitial injury induced by AII infusion.

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.

Angiotensin II type 1 receptor blocker ameliorates uncoupled endothelial nitric oxide synthase in rats with experimental diabetic nephropathy.

BACKGROUND: Recent studies showed that angiotensin II type 1 receptor blocker (ARB) slows progression of chronic renal disease in patients with type 2 diabetes, regardless of changes in blood pressure. We showed that the imbalance of nitric oxide (NO) and reactive oxygen species (ROS) due to endothelial NO synthase (eNOS) uncoupling contributed to renal dysfunction in the diabetic nephropathy. The aim of this study was to determine the effects of ARB on uncoupled eNOS in rat diabetic nephropathy. METHODS: Diabetes was induced in Sprague-Dawley rats with streptozotocin (65 mg/ kg body weight). After 6 weeks, rats were divided into saline (DM; n = 11) and ARB, losartan groups (DM+Los; n = 11). After 2-week treatment, glomerular ROS production was assessed by 2',7'-dichlorofluorescin diacetate (DCFH-DA)-derived chemiluminescence. Renal NO and ROS production were imaged by confocal laser microscopy after renal perfusion with DCFH-DA and diaminorhodamine-4M acetoxymethyl ester with L-arginine. The dimeric form of eNOS was measured by low-temperature sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Serum tetrahydrobiopterin (BH4) concentrations were determined by high-performance liquid chromatography. Protein and mRNA expression of GTP cyclohydrolase 1 (GTPCH1), key enzyme of BH4 synthesis, were examined. RESULTS: Losartan attenuated glomerular ROS production in DM. Accelerated ROS production and diminished bioavailable NO caused by NOS uncoupling were noted in DM glomeruli. Losartan reversed the decreased GTPCH1 and decreased dimeric form of eNOS and glomerular NO production by increased BH4 bioavailability. CONCLUSIONS: ARB improved the NOS uncoupling in diabetic nephropathy by increasing BH4 bioavailability.

Isohumulones derived from hops ameliorate renal injury via an anti-oxidative effect in Dahl salt-sensitive rats.

Previous studies have reported that isohumulones, the bitter compounds in beer, improve insulin resistance and hyperlipidemia in several animal models. In this study, we examined whether isohumulones ameliorate renal injury. Dahl salt-sensitive hypertensive rats were fed a low-salt diet (LS), a high-salt diet (HS) or a high-salt diet containing 0.3% isohumulones (HS+IH) for 4 weeks. Urinary nitrite/nitrate (NOx) excretion was measured at 4 weeks along with blood pressure and urinary protein excretion. Renal injury was evaluated histologically and reactive oxygen species (ROS) and nitric oxide (NO) production in the renal cortex was visualized. Oxidative stress and NO synthase (NOS) expression were evaluated by immunohistochemical staining and Western blot analysis. Mean blood pressure was significantly decreased in the HS+IH group compared with the HS group at 4 weeks (158.1+/-8.7 vs. 177.5+/-3.7 mmHg; p<0.05). Isohumulones prevented the development of proteinuria in the HS+IH group compared with the HS group at 2 weeks (61.7+/-26.8 vs. 117.2+/-9.8 mg/day; p<0.05). Glomerulosclerosis and interstitial fibrosis scores were significantly decreased in the HS+IH group compared with the HS group (0.61+/-0.11 vs. 1.55+/-0.23, 23.7+/-6.8 vs. 36.1+/-3.5%; p<0.05 for both). In the HS group, increased ROS and decreased NO were observed in glomeruli in vivo. Isohumulones reduced the ROS production, leading to the restoration of bioavailable NO. Urinary NOx excretion was significantly increased in the HS+IH group compared with the HS group. Furthermore, renal nitrotyrosine was increased in the HS group compared with the LS group, and this effect was prevented by isohumulones. Renal NOS expression did not differ among the three groups. These results suggest that isohumulones may prevent the progression of renal injury caused by hypertension via an anti-oxidative effect.

Implication of peritubular capillary loss and altered expression of vascular endothelial growth factor in IgA nephropathy.

BACKGROUND/AIMS: To determine the roles of peritubular capillary (PTC) loss and expression of vascular endothelial growth factor (VEGF) and its transcription factor, hypoxia-inducible factor-1 (HIF-1), in the progression of IgA nephropathy (IgAN), we analyzed the expression of VEGF and HIF-1, and the number of PTCs in patients with variable severity of IgAN. METHODS: Renal biopsy specimens from patients with IgAN (n = 23) were classified according to interstitial injury score: grade 0 (0%), grade 1 (1-25%), grade 2 (25-50%) and grade 3 (50-100%). We examined the immunohistochemical expression of CD34, VEGF and HIF-1alpha. RESULTS: VEGF was expressed in the cytoplasm of tubular epithelia, and VEGF-positive area significantly expanded in grades 1 (35.5 +/- 5.9%, mean +/- SD) and 2 (32.5 +/- 5.9%) compared with grade 0 (23.4 +/- 4.5%). The numbers of PTCs were significantly lower in grades 2 (559 +/- 49/mm2) and 3 (510 +/- 56/mm2) than grade 0 (708 +/- 49/mm2). HIF-1alpha was weakly expressed in tubular epithelia in grade 0, increased with progression to grade 2, and markedly decreased in grade 3. It was also increased in pericapsular interstitial area in grade 1. The expression pattern of HIF-1alpha did not parallel that of VEGF. In renal biopsies of 5 control patients with minor glomerular abnormality, glomerular expression levels of VEGF and HIF-1alpha were similar to those of IgAN grade 0 kidneys. CONCLUSION: VEGF production was accelerated in the early stage of IgAN but it did not protect against PTC injury/loss. The lack of correlation between VEGF and HIF-1alpha expression suggests HIF-independent VEGF production in IgAN.

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.

Telmisartan improves endothelial dysfunction and renal autoregulation in Dahl salt-sensitive rats.

Hypertensive vascular disorders are characterized by endothelial dysfunction. Loss of renal autoregulation causes glomerular hypertension. However, the relationship between the autoregulatory response and glomerular damage has not been well examined. We examined the contributions of uncoupled endothelial nitric oxide synthase (eNOS) in hypertensive renal disease, and the relationship between the degree of autoregulation impairment and glomerular injury. We also investigated the effects of telmisartan on eNOS coupling and renal autoregulation. Male Dahl salt-sensitive hypertensive (DS) rats (14-week old) fed an 8% salt diet were used to examine endothelial dysfunction and impaired renal autoregulation caused by glomerular hypertension. Some DS rats were treated with telmisartan (3.0 mg kg(-1) day(-1)), an angiotensin receptor blocker, for 2 weeks. Increased superoxide production and decreased nitric oxide production, as detected by fluorescent indicator perfusion methods, were observed in the glomeruli and arterioles of hypertensive DS rats. Telmisartan improved the imbalance of superoxide and nitric oxide in the glomeruli and arterioles. Decreased serum tetrahydrobiopterin levels and coupled eNOS seen in the DS rat kidney were improved with telmisartan treatment. The endothelial relaxation reaction was impaired in DS rat aortic arteries. Autoregulatory capacity in response to step changes in perfusion pressure was also impaired in DS rat kidney. Treatment with telmisartan improved these abnormalities. Endothelial dysfunction in the glomeruli and impaired renal autoregulation, which may cause glomerular sclerosis, were observed in DS rat kidney. Telmisartan treatment improves these dysfunctions in hypertensive renal 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.

NAD(P)H oxidase and uncoupled nitric oxide synthase are major sources of glomerular superoxide in rats with experimental diabetic nephropathy.

Increased production of reactive oxygen species (ROS) in diabetes may be a common pathway linking diverse pathogenic mechanisms of diabetic vascular complications, including nephropathy. Assessment of the oxidative stress production pathway is therefore important for the prediction and prevention of diabetic complications. However, ROS production mechanisms remain unclear in diabetic glomeruli. To identify the source and determine the mechanisms of ROS production in the diabetic kidney, diabetes was induced with streptozotocin in rats. After 6 wk, glomerular ROS production had increased in the streptozotocin rat kidney, as assessed by dihydroethidium-derived chemiluminescence. ROS production was increased by the addition of NADH or L-arginine and was partially reduced by the addition of diphenylene iodonium or N(G)-nitro-L-arginine methyl ester, identifying NAD(P)H oxidase and nitric oxide (NO) synthase (NOS) as ROS sources. The mRNA and protein expression of endothelial NOS (eNOS), as measured by real-time RT-PCR and Western blotting, increased significantly (mRNA level, 1.3-fold; protein level, 1.8-fold). However, the dimeric form of eNOS was decreased in diabetic glomeruli, as measured by low-temperature SDS-PAGE. Production of renal ROS and NO by uncoupled NOS was imaged by confocal laser microscopy after renal perfusion of 2',7'-dichlorofluorescein diacetate (a ROS marker) and diaminorhodamine-4M AM (a NO marker) with L-arginine. Accelerated ROS production and diminished bioavailable NO caused by NOS uncoupling were noted in the diabetic kidney. Administration of tetrahydrobiopterin (BH4), a cofactor for eNOS, reversed the decreased dimeric form of eNOS and glomerular NO production. Our results indicate that NAD(P)H oxidase and uncoupling of eNOS contribute to glomerular ROS production, mediated by the loss of BH4 availability. These mechanisms are potential key targets for therapeutic interventions.

A novel free radical scavenger, edarabone, protects against cisplatin-induced acute renal damage in vitro and in vivo.

Accumulating evidence suggests that enhanced peroxidative damage caused by reactive oxygen species (ROS) may contribute to the pathogenesis of cisplatin-induced acute renal failure. Nevertheless, little is known about the involvement of oxygen radicals in cisplatin nephropathy. In this study, we investigated the effects of a novel free radical scavenger, 3-methyl-1-phenyl-pyrazolin-5-one (MCI-186; edarabone), on murine proximal tubular cell (PTC) damage induced by exposure to cisplatin in vitro and on renal function in an in vivo model of cisplatin-induced acute renal failure. Edarabone inhibited cisplatin-induced (40 microM, 24 h) cytotoxicity in a concentration-dependent manner (10-5 to 10-3 M). Edarabone also attenuated cisplatin-induced mitochondrial transmembrane potential loss and ROS production of PTCs. In the in vivo study, male Wistar rats were cotreated with cisplatin (5 mg/kg, i.p.) and edarabone (1 or 5 mg/kg, i.v.). Effects of edarabone on the kidney were examined 5 days after treatment. Cisplatin resulted in renal dysfunction, renal tubular damage, mitochondrial damage (assayed by histochemical staining for respiratory chain complex IV), renal protein oxidation (examined by Western blot analysis using a specific antibody for carbonyl group-containing proteins), and tubular apoptosis (determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining). The above changes were attenuated by edarabone treatment. Thus, edarabone exhibited cytoprotective effects in PTCs and renoprotective effects against cisplatin. Our findings suggest that ROS, in particular hydroxyl radicals, are involved in cisplatin nephropathy and that edarabone may be potentially useful in protecting the kidneys and prevention of acute renal failure.