Nobuharu Fujiwara

Ezetimibe decreases serum levels of asymmetric dimethylarginine (ADMA) and ameliorates renal injury in non-diabetic chronic kidney disease patients in a cholesterol-independent manner

Synthesis of nitric oxide (NO) can be blocked by inhibition of nitric oxide synthase (NOS) active site with guanidino-substituted analogues of l-arginine such as asymmetric dimethylarginine (ADMA). There is growing evidence that elevation of serum ADMA levels play a role in the progression of atherosclerosis and chronic kidney disease (CKD) in high-risk patients. Further, dyslipidemia contributes to cardiorenal disease as well. However, effects of ezetimibe, a specific inhibitor of cholesterol absorption and widely used drug for the treatment of dyslipidemia, on serum ADMA levels and renal injury remain unknown. In this study, we examined whether ezetimibe treatment decreased serum levels of ADMA, proteinuria and urinary excretion levels of 8-hydroxydeoxyguanosine (8-OHdG) and l-fatty acid binding protein (l-FABP), markers of oxidative stress and tubular injury, respectively and investigated their relationships in 10 non-diabetic CKD patients with dyslipidemia. Ezetimibe treatment (10mg/day) for 6 months significantly decreased circulating levels of LDL-cholesterol, triglycerides and ADMA, while it increased HDL-cholesterol levels. Further, ezetimibe treatment significantly reduced urinary excretion levels of protein, l-FABP and 8-OHdG. In univariate analyses, serum ADMA levels were correlated with urinary protein, l-FABP and 8-OHdG levels. In multiple stepwise regression analysis, proteinuria was independently correlated with ADMA. Our present study demonstrated for the first time that ezetimibe decreased serum ADMA levels and improved renal injury in non-diabetic CKD patients with dyslipidemia in a cholesterol-independent manner. Ezetimibe may have pleiotropic actions, that is, ADMA-lowering and anti-oxidative effects, that could contribute to renoprotective properties of this lipid-lowering agent.

Oral adsorbent AST-120 ameliorates tubular injury in chronic renal failure patients by reducing proteinuria and oxidative stress generation

AST-120 is an oral adsorbent that attenuates the progression of chronic renal failure (CRF) and improves the prognosis of the patients under dialysis. Although tubulointerstitial injury is more important than glomerulopathy in terms of renal prognosis in patients with CRF, effect of AST-120 on tubular injury in CRF patients remains unknown. In this study, we examined whether and how AST-120 treatment could improve tubular damage in nondiabetic CRF patients. Fifty nondiabetic CRF patients were enrolled in the present study and divided into 2 groups: one was the AST-120-treated group (15 men and 10 women) and the other was the age-, sex-, and clinical variables-matched non-AST-120-treated control group. Patients were followed up for 12 months. We investigated the effects of AST-120 on serum levels of interleukin-6 (IL-6), proteinuria, and urinary excretion levels of 8-hydroxydeoxyguanosine (8-OHdG) and L-fatty acid binding protein (L-FABP), markers of oxidative stress and tubular injury, respectively. AST-120 treatment (6 g/d), but not control treatment, for 12 months significantly reduced IL-6, proteinuria, and urinary excretion levels of L-FABP and 8-OHdG, and inhibited the increase in serum creatinine in CRF patients. In univariate analyses, L-FABP levels were correlated with age, proteinuria, 8-OHdG, and IL-6. In multiple stepwise regression analysis, proteinuria and urinary 8-OHdG levels were independently related to L-FABP levels (R² = 0.605). Our present study demonstrated for the first time that AST-120 improved tubular injury in nondiabetic CRF patients. AST-120 may exert beneficial effects in CRF patients by protecting tubular damage partly via reduction of proteinuria and oxidative stress generation.

Co-administration of ezetimibe enhances proteinuria-lowering effects of pitavastatin in chronic kidney disease patients partly via a cholesterol-independent manner

Since co-administration of ezetimibe, a specific inhibitor of cholesterol absorption into the intestine, has been shown to augment lipid-lowering effects of statins, ezetimibe plus statins is a novel therapeutic strategy for the treatment of dyslipidemia in high-risk patients. Statins have been shown to ameliorate renal function and reduce proteinuria in patients with chronic kidney disease (CKD). However, effects of co-administration of ezetimibe with statins on renal damage and dysfunction in CKD patients remain unknown. In this study, we examined whether co-administration of ezetimibe with pitavastatin could augment renoprotective properties of pitavastatin in non-diabetic CKD patients with dyslipidemia. Total cholesterol, LDL-cholesterol and triglycerides levels were reduced more by co-administration of ezetimibe (10mg/day) with pitavastatin (2mg/day) (n=10) than by pitavastatin alone (n=10). In addition, ezetimibe plus pitavastatin treatment produced significant incremental reduction in proteinuria related to pitavastatin therapy alone. In univariate analyses, proteinuria was correlated with plasma levels of total cholesterol, LDL-cholesterol, triglycerides, HDL-cholesterol (inversely), asymmetric dimethylarginine, an endogenous nitric oxide synthase inhibitor, and urinary excretion levels of L-fatty acid binding protein (L-FABP), a marker of tubular injury and 8-hydroxydeoxyguanosine (8-OHdG), an oxidative stress marker. Multiple stepwise regression analysis revealed that LDL-cholesterol (p<0.001) and urinary excretion levels of L-FABP (p=0.001) and 8-OHdG (p<0.001) were independently related to proteinuria (R(2)=0.969). Our present study demonstrated for the first time that co-administration of ezetimibe enhanced proteinuria-lowering effects of pitavastatin in non-diabetic CKD patients partly via a cholesterol-independent manner. Ezetimibe may have pleiotropic actions that could contribute to renoprotective properties of this lipid-lowering agent.

Positive association of serum levels of advanced glycation end products and high mobility group box–1 with asymmetric dimethylarginine in nondiabetic chronic kidney disease patients

There is accumulating evidence that engagement of the receptor for advanced glycation end products (RAGE) with ligands such as advanced glycation end products (AGEs) and high mobility group box-1 (HMGB-1) elicits vascular inflammation, thus contributing to the increased risk for cardiovascular disease. Furthermore, enhanced accumulation of asymmetric dimethylarginine (ADMA) plays a role in cardiovascular disease in chronic kidney disease (CKD) patients. However, the relationships among serum levels of AGEs, HMGB-1, soluble form of RAGE (sRAGE), and ADMA are largely unknown. The aim of the present study is to determine their relationships in CKD patients. Twenty nondiabetic normotensive CKD patients with dyslipidemia and 20 age- and sex-matched healthy controls were enrolled. All subjects underwent determination of blood chemistries; urinary proteinuria; and serum levels of AGEs, HMGB-1, sRAGE, and ADMA. Serum AGE, HMGB-1, sRAGE, and ADMA levels in CKD patients were significantly higher than those in control subjects. Circulating levels of AGEs in CKD patients were positively associated with sRAGE and ADMA, and HMGB-1 with ADMA, but not sRAGE. There were no significant associations among these markers and serum creatinine, estimated glomerular filtration rate, proteinuria, and lipid levels. In multiple regression analyses, AGEs and HMGB-1 were independently correlated with ADMA. The present study demonstrated that AGE and sRAGE levels were correlated with each other and that AGEs and HMGB-1 were independently associated with ADMA in nondiabetic CKD patients. Elevation of the RAGE ligands may enhance ADMA levels, suggesting the active involvement of AGE/HMGB-1-RAGE-ADMA axis in CKD patients.

Circulating levels of advanced glycation end products (AGE) and interleukin-6 (IL-6) are independent determinants of serum asymmetric dimethylarginine (ADMA) levels in patients with septic shock.

There is a growing body of evidence that nitric oxide (NO) excess plays a central role in the pathogenesis of hypotension and organ failure in patients with septic shock. In addition, recently, asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, has been shown to contribute to the regulation of vascular tone via modulation of NO generation in vivo. However, the kinetics and regulation of serum levels of ADMA in patients with septic shock are largely unknown. Since high mobility group box 1 (HMGB1)-receptor for advanced end products (RAGE) axis is supposed to be involved in the lethality in septic shock, we examined the correlations among serum levels of ADMA, endotoxin, interleukin-6 (IL-6), soluble form of RAGE (sRAGE) and RAGE ligands such as HMGB1 and advanced glycation end products (AGE) in septic shock patients. Fifteen septic shock patients (10 males and 15 females, mean age: 70.1+/-8.5 years) and fifteen age- and sex-matched healthy volunteers were included in this study. The criteria of the American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference were used for diagnosis of septic shock. All the subjects underwent a complete history and physical examination, determination of blood chemistries, including serum levels of ADMA, endotoxin, IL-6, HMGB1, AGE and sRAGE. Linear and multiple stepwise regression analysis were performed for the determinants of serum levels of ADMA. Serum levels of ADMA were significantly higher than those in healthy volunteers (0.98+/-0.21nmol/mL vs. 0.30+/-0.05nmol/mL, p<0.0001). In univariate analysis, creatinine (p<0.005), endotoxin (p<0.001), IL-6 (p<0.001), HMGB1 (p<0.001), AGE (p<0.001) and sRAGE (p<0.001) were significantly associated with serum ADMA levels. After performing multivariate stepwise regression analyses, IL-6 (p=0.001), AGE (p=0.002) and creatinine (p=0.013) still remained significant independently. The present study is the first demonstration that ADMA levels were significantly elevated in patients with septic shock and that serum IL-6, AGE and creatinine levels were independent determinants of ADMA in these patients. Given the harmful effects of NO excess in septic shock, ADMA levels may be increased as a counter-system against inflammation and oxidative stress in this life-threatening disorder.

Changes in Urinary Albumin Excretion, Inflammatory and Oxidative Stress Markers in ADPKD Patients with Hypertension

Backgrounds:Autosomal dominant polycystic kidney disease (ADPKD) progresses more quickly to end-stage renal disease in patients with hypertension than in their normotensive counterparts. The authors investigated the effect of telmisartan versus enalapril on systolic and diastolic blood pressure (SBP and DBP), urinary albumin excretion (UAE), serum high mobility group box-1 protein (HMGB1), serum interleukin (IL)-6 and urinary 8-hydroxydeoxyguanosine (8-OHdG) levels in patients with hypertensive ADPKD. Methods:Twenty patients with hypertensive ADPKD with good renal function were randomly assigned to 1 of 2 treatments: telmisartan 80 mg once daily (n = 10) or enalapril 10 mg once daily (n = 10). Treatment lasted 12 months. SBP, DBP, serum creatinine, UAE, HMGB1, IL-6 and urinary 8-OHdG levels were measured before and 6 and 12 months after treatment. Results:Both SBP and DBP were significantly reduced after treatment (P < 0.001) in both groups. Serum creatinine changed little during the experimental period in either group. UAE, serum HMGB1, serum IL-6 and urinary 8-OHdG levels were significantly decreased after treatment (UAE, HMGB1 and IL-6, P < 0.001; and 8-OHdG, P < 0.01 versus baseline levels) in both groups. However, the decreases in UAE, serum HMGB1 and serum IL-6 were significantly greater in the telmisartan group than in the enalapril group at 6 months (P < 0.05, P < 0.01 and P < 0.01, respectively) and 12 months (all, P < 0.05). Conclusions:Telmisartan seems to be equivalent to enalapril in lowering BP, but telmisartan has more potent renoprotective, anti-inflammatory and antioxidative effects than enalapril in patients with hypertensive ADPKD.

Effect of polymyxin B-immobilized fiber hemoperfusion on serum high mobility group box-1 protein levels and oxidative stress in patients with acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is characterized by diffuse inflammation in the lung and resultant permeability edema. Polymyxin B-immobilized fiber (PMX-F) hemoperfusion is effective for sepsis-induced ARDS. High mobility group box-1 protein (HMGB1) is newly recognized as a proinflammatory cytokine. The aim of the study was to determine whether blood HMGB1 levels are increased in patients with ARDS and whether PMX-F treatment affects these levels. Subjects were 20 sepsis-induced patients with ARDS treated by PMX-F column and 20 age-matched healthy volunteers. Polymyxin B-immobilized fiber treatment was carried out twice at a rate of 100 ml/min for 2 hours. Systolic and diastolic blood pressures, the PaO2/FiO2 (PF) ratio and endotoxin, HMGB1, and urinary 8-hydroxy-2′-deoxyguanosine (OHdG) levels were measured before and after PMX-F treatment. Blood endotoxin levels, blood HMGB1 levels, and urinary 8-OHdG levels were significantly higher in patients with ARDS than in healthy volunteers. Systolic and diastolic blood pressures and the PF ratio increased significantly after PMX-F treatments. Polymyxin B-immobilized fiber treatment reduced blood endotoxin, blood HMGB1, and urinary 8-OHdG levels significantly. These data suggest that HMGB1 and oxidative stress play a role in the pathogenesis of ARDS and that PMX-F treatment may ameliorate increased blood HMGB1 and urinary 8-OHdG levels in patients with ARDS.

Comparative Effects of Benidipine and Amlodipine on Proteinuria, Urinary 8-OHdG, Urinary L-FABP, and Inflammatory and Atherosclerosis Markers in Early-Stage Chronic Kidney Disease

Introduction:We examined the effects of 2 calcium channel blockers, benidipine (T-, L-, and N-type) and amlodipine (L- and N-type), on renal, inflammatory, oxidative, and atherosclerosis markers in hypertensive patients with mild chronic kidney disease (CKD). Methods:Forty hypertensive patients with CKD were assigned randomly to either of the 2 treatments: 8 mg benidipine once daily (n = 20, group A) or 5 mg amlodipine once daily (n = 20, group B). Treatment was continued for 12 months. Blood pressure, serum creatinine, estimated glomerular filtration rate, urinary protein excretion, urinary liver-type fatty acid-binding protein, interleukin-6, high mobility group box-1 protein, urinary 8-hydroxy-2′-deoxyguanosine, pulse wave velocity, intima-media thickness, and blood asymmetric dimethylarginine were monitored. Results:Blood pressure decreased equally in both groups (P < 0.001, at 6 and 12 months versus before treatment). Serum creatinine and estimated glomerular filtration rate changed little during the experimental period in each group. However, urinary protein excretion (P < 0.001), urinary liver-type fatty acid-binding protein (P < 0.001), urinary 8-hydroxy-2′-deoxyguanosine (P < 0.001), blood interleukin-6 (P < 0.001), blood high mobility group box-1 (P < 0.05), and pulse wave velocity (P < 0.01) decreased more in group A than in group B with 12 months of treatment. The percent reductions in intima-media thickness and blood asymmetric dimethylarginine were significantly greater in group A than in group B (P < 0.001). Conclusions:Benidipine is more effective than amlodipine for protecting renal function and potentially for ameliorating atherosclerosis in hypertensive patients with mild CKD. T-type calcium channel blockers may be effective in patients with CKD.

Atorvastatin Reduces Proteinuria in Non-Diabetic Chronic Kidney Disease Patients Partly via Lowering Serum Levels of Advanced Glycation End Products (AGEs)

There is accumulating evidence that advanced glycation end products (AGEs) play a role in the development and progression of chronic kidney disease (CKD). We have previously found that atorvastatin treatment significantly reduces serum levels of AGEs in type 2 diabetic patients and subjects with non-alcoholic steatohepatitis in a cholesterol loweringindependent manner. In this study, we examined whether atorvastatin could reduce proteinuria partly via reduction of serum levels of AGEs in non-diabetic CKD patients. Ten non-diabetic normotensive stage I or II CKD patients with dyslipidemia were enrolled. Patients were treated with atorvastatin (10 mg/day) for one year. All subjects underwent determination of blood chemistries, proteinuria and serum levels of AGEs at baseline and after one year. Atorvastatin treatment for one year significantly decreased circulating levels of total cholesterol, LDL cholesterol, triglycerides and AGEs, while it increased HDL cholesterol levels. Further, although atorvastatin treatment did not affect estimated glomerular filtration rate, it significantly reduced proteinuria. In univariate analyses, proteinuria levels were correlated with total cholesterol, LDL cholesterol, triglycerides, HDL cholesterol (inversely) and AGEs. Multiple stepwise regression analysis revealed that AGE level was a sole independent correlate of proteinuria. In this initial examination of the patients in this study, our present study suggests that atorvastatin could decrease proteinuria in non-diabetic CKD patients with dyslipidemia partly via reduction of serum levels of AGEs. Atorvastatin may have AGE-lowering effects in CKD patients as well that could contribute to renoprotective properties of this agent.

Effects of telmisartan and enalapril on renoprotection in patients with mild to moderate chronic kidney disease

Eur J Clin Invest 2010; 40 (9): 790–796