Additive effect of ACE inhibition and angiotensin II receptor blockade in type I diabetic patients with diabetic nephropathy

Albuminuria and hypertension are predictors of poor renal and cardiovascular outcome in diabetic patients. This study tested whether dual blockade of the renin-angiotensin system (RAS) with both an angiotensin-converting enzyme (ACE) inhibitor (ACE-I) and an Angiotensin-II receptor blocker (ARB) is superior to either drug alone in type I diabetic patients with diabetic nephropathy (DN). A randomized double-blind crossover trial was performed with 8-wk treatment with placebo, 20 mg of benazepril once daily, 80 mg of valsartan once daily, and the combination of 20 mg of benazepril and 80 mg of valsartan. Twenty type I diabetic patients with DN were included. At the end of each treatment period, albuminuria, 24-h BP, and GFR were measured. Eighteen patients completed the study. Placebo values were: albuminuria [mean (95% CI)], 701 (490 to 1002) mg/24 h; BP [mean (SEM)], 144 (4)/79 (2) mmHg, and GFR [mean (SEM)], 82 (7) ml/min per 1.73 m(2). Treatment with benazepril, valsartan, or dual blockade significantly reduced albuminuria and BP compared with placebo. Benazepril and valsartan were equally effective. Dual blockade induced an additional reduction in albuminuria of 43 % (29 to 54 %) compared with any type of monotherapy, and a reduction in systolic BP of 6 (0 to 13) mmHg and 7 (1 to 14) mmHg (versus benazepril and valsartan, respectively) and a reduction of 7 (4 to 10) mmHg diastolic compared with both monotherapies. GFR was reversibly reduced on dual blockade compared with monotherapy and placebo. All treatments were safe and well tolerated. In conclusion, dual blockade of the RAS may offer additional renal and cardiovascular protection in type I diabetic patients with DN.     

Dual blockade of the renin-angiotensin system versus maximal recommended dose of ACE inhibition in diabetic nephropathy

BACKGROUND: Albuminuria and hypertension are predictors of poor renal and cardiovascular outcome in diabetic patients. We tested whether dual blockade of the renin-angiotensin system (RAS) with both an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin II receptor blocker (ARB) is superior to maximal recommended dose of ACE inhibitor in type 1 diabetic patients with diabetic nephropathy (DN). METHODS: We performed a randomized, double-blind, crossover trial with 8 weeks treatment with placebo and irbesartan 300 mg (once daily), added on top of enalapril 40 mg (once daily). We included 24 type 1 patients with DN. At the end of each treatment period, albuminuria, 24-hour blood pressure, and glomerular filtration rate (GFR) were measured. RESULTS: Values on ACE inhibitors + placebo were: albuminuria [mean (95% CI)], 519 (342 to 789) mg/24 hours; blood pressure [mean (SEM)], 131 (3)/74 (1) mm Hg, and GFR [mean (SEM)], 65 (5) mL/min/1.73 m2. Dual blockade of the RAS induced a reduction in albuminuria [mean (95% CI)] of 25% (15, 34) (P < 0.001), a reduction in systolic blood pressure of 8 mm Hg (4, 12) (P = 0.002), and a reduction of 4 mm Hg (2, 7) (P = 0.003) in diastolic blood pressure. GFR and plasma potassium remained unchanged during both treatment regimes. Dual blockade was safe and well tolerated. CONCLUSION: Dual blockade of the RAS is superior to maximal recommended dose of ACE inhibitors with regard to lowering of albuminuria and blood pressure in type 1 patients with DN. Long-term trials are needed to further establish the role of dual blockade of the RAS in renal and cardiovascular protection.     

Beneficial impact of spironolactone in diabetic nephropathy

BACKGROUND: Aldosterone has been suggested to play a role in the initiation and progression of diabetic nephropathy. Currently recommended treatment with angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers [renin-angiotensin system (RAS) blockade] does not suppress circulating aldosterone sufficiently. We therefore aimed to evaluate the short-term effect of aldosterone antagonism with spironolactone on albuminuria and blood pressure in diabetic nephropathy. METHODS: Twenty Caucasian type 1 diabetic patients with persistent macroalbuminuria despite antihypertensive treatment, including RAS blockade, completed this double-masked, randomized cross-over trial. Patients were treated in random order with spironolactone 25 mg once daily and matched placebo for two months, respectively, on top of usual antihypertensive treatment. After each treatment period albuminuria, 24-hour blood pressure, and glomerular filtration rate (GFR) were determined. RESULTS: Spironolactone on top of usual antihypertensive treatment induced a 30% (95% CI 17 to 41) reduction in albuminuria from [geometric mean (95% CI)] 831 (624 to 1106) mg/24-hour on placebo treatment (P < 0.001), and a reduction in fractional albumin clearance of 35% (20 to 46, P < 0.001). Twenty-four-hour blood pressure showed an insignificant reduction of [mean reduction (95% CI)] 8 (-1 to 17)/3 (-0.2 to 7) mm Hg (P < 0.10). There was an insignificant reversible reduction in GFR during treatment with spironolactone. On spironolactone treatment, one patient was excluded due to hyperkalemia (plasma potassium 5.7 mmol/L) and one due to orthostatic dizziness. Otherwise treatment was well tolerated. CONCLUSION: Our results suggest that spironolactone treatment on top of recommended antihypertensive treatment reduces blood pressure and may offer additional renoprotection in type 1 diabetic patients with diabetic nephropathy.     

Beneficial impact of spironolactone on nephrotic range albuminuria in diabetic nephropathy

Reduction of nephrotic range albuminuria is associated with markedly improved renal and cardiovascular outcome in patients with diabetic nephropathy. Aldosterone has been suggested to play a role in the progression of diabetic nephropathy. We therefore aimed to evaluate the short-term effect of aldosterone antagonism with spironolactone on nephrotic range albuminuria and blood pressure in diabetic nephropathy. Twenty Caucasian patients with diabetic nephropathy and nephrotic range albuminuria (>2500 mg/24 h) despite recommended antihypertensive treatment completed this double-masked, randomized crossover trial. Patients were treated in random order with spironolactone 25 mg once daily and matched placebo for 2 months, on top of ongoing antihypertensive treatment, including an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker in maximally recommended doses. Median (range) number of antihypertensive drugs was 3 (2-5). After each treatment period, albuminuria, 24-h ambulatory blood pressure, and glomerular filtration rate (GFR) were determined. Spironolactone on top of recommended renoprotective treatment induced a 32% (95% confidence interval (CI): 21-42%) reduction in albuminuria from (geometric mean (95% CI)) 3718 (2910-4749) mg/24 h on placebo treatment (P<0.001). There was a significant reduction in 24-h blood pressure of 6 (2-10)/4 (2-6) mm Hg and day blood pressure of 7 (3-12)/5 (3-7) mm Hg (P<0.01), whereas night blood pressure remained unchanged. Spironolactone induced an insignificant reversible reduction in GFR of 3 ml/min/1.73 m2 from 64 (27) ml/min/1.73 m2. No patients were excluded due to adverse events. Our results suggest that spironolactone treatment on top of recommended renoprotective treatment including maximal renin-angiotensin system blockade may offer additional renoprotection in patients with diabetic nephropathy and nephrotic range albuminuria.     

Targeting albumin excretion rate in the treatment of the hypertensive diabetic patient with renal disease

Combination of an angiotensin-converting enzyme inhibitor (ACEI) with an angiotensin II receptor blocker is advocated as a treatment option in diabetic patients with nephropathy and residual albuminuria while on antihypertensive therapy. Abrogation of albuminuria is a key treatment goal to prevent disease progression. The assumption is that albuminuria reduction is the result of more complete blockade of the renin angiotensin system; thus, the ACEI-angiotensin II receptor blocker combination would have a greater albuminuria-lowering effect than the combination of an ACEI with a calcium channel blocker such as amlodipine, which causes similar reductions in BP but does not affect the renin angiotensin system. Twenty-eight patients who had type 1 diabetes and known diabetic renal disease and had a persistently elevated albumin creatinine ratio (ACR) > 10 mg/mmol despite office BP recordings < or = 140/80 mmHg on maximal recommended dose of the ACEI lisinopril were studied. Patients were allocated to receive either candesartan (16 mg/d) or amlodipine (10 mg/d) in addition to preexisting ACEI inhibition and followed for 24 wk in a randomized, double-blind, parallel-group trial. By week 24, ACR fell by 56% with candesartan and 54% with amlodipine (P < 0.01 versus baseline for both) with no significant difference between groups. Mean arterial BP fell between 3 and 6 mmHg similarly in both groups. In neither group was a significant correlation found between the change in ACR and the change in BP. Candesartan and amlodipine lowered ACR and BP by a similar degree. The fall in ACR was disproportionate to the fall of systemic BP and independent of it. The mechanism of the reduction in albuminuria seen with these agents in combination with an ACEI remains to be elucidated.     

Optimal dose of losartan for renoprotection in diabetic nephropathy.

BACKGROUND: Angiotensin II subtype-1 receptor antagonists represent a valuable new class of drugs in the treatment of diabetic nephropathy. The aim of our study was to evaluate the optimal dose of losartan for renoprotection and blood pressure reduction in diabetic nephropathy. METHODS: Fifty consecutive hypertensive type 1 diabetic patients with diabetic nephropathy received increasing doses of losartan, 50, 100, and 150 mg once daily in three periods each lasting 2 months. At baseline and at the end of each treatment period, albuminuria, 24-h blood pressure (TM2420 A&D), and glomerular filtration rate (GFR) ([(51)Cr]EDTA plasma clearance) were determined. RESULTS: Baseline values of albuminuria (geometric mean (95% CI)) and GFR (means+/-SEM) were 1138 (904-1432) mg/24 h and 91+/-3 ml/min/1.73 m(2), respectively. The blood pressure at baseline was 155/81+/-3/2 mmHg. All doses of losartan reduced albuminuria and blood pressure. Albuminuria was reduced by 30% (95% CI (15-41)) on losartan 50 mg, 48% (35-57) by losartan 100 mg, and 44% (32-56) by losartan 150 mg (all P values <0.01 vs baseline). Losartan 100 mg daily was significantly more effective than 50 mg daily in reducing albuminuria (P<0.01) without differences between the two high doses. Losartan 50, 100, and 150 mg daily decreased systolic/diastolic blood pressures by 7/4, 12/6, and 10/5 mmHg, respectively (all P<0.05). Losartan 100 mg daily was more effective than 50 mg daily in reducing systolic, diastolic, and mean arterial blood pressure (P=0.05), without differences between the high doses. Treatment with losartan 100 and 150 mg lowered GFR by 4 ml/min/1.73 m(2) (P<0.05). CONCLUSION: Our study suggests that the optimal dose of losartan is 100 mg daily for renoprotection and blood pressure reduction in type 1 diabetic patients with diabetic nephropathy.     

Remission to normoalbuminuria during multifactorial treatment preserves kidney function in patients with type 2 diabetes and microalbuminuria.

BACKGROUND: Intervention studies in microalbuminuric type 2 diabetic patients have demonstrated that it is possible to avoid progression to overt diabetic nephropathy and even to achieve regression to normoalbuminuria. However, the long-term impact of stabilization/regression in albuminuria on decline in glomerular filtration rate (GFR) has not been established. METHODS: 151 patients with type 2 diabetes and microalbuminuria at baseline in whom GFR was measured at least three times during 7.8 years of follow-up were divided into three groups according to the level of albuminuria during follow-up. Overt nephropathy was diagnosed as a urinary albumin excretion rate (AER) >300 mg/24 h and remission to normoalbuminuria was defined as an AER <30 mg/24 h at the last examination. RESULTS: During follow-up, 46 patients achieved remission to normoalbuminuria, 58 remained microalbuminuric and 47 patients progressed to overt nephropathy. The mean (+/- SE) yearly decline in GFR was lowest (2.3+/-0.4 ml/min/year) in patients who obtained remission, in comparison with patients remaining microalbuminuric, in whom the decline was 3.7+/-0.4 ml/min/year, and patients progressing to overt nephropathy, who had a decline in GFR of 5.4+/-0.5 ml/min/year (ANOVA, P<0.001). Start of antihypertensive treatment during follow-up was strongly associated with remission to normoalbuminuria [odds ratio: 2.32; 95% confidence interval (CI): 1.09-4.93] whereas a decrease in HbA(1c) by 1% increased the probability for remission (odds ratio: 1.48; 95% CI: 1.11-1.97). CONCLUSIONS: Remission to normoalbuminuria was associated with a decreased GFR decline during 7.8 years of follow-up in type 2 diabetic patients with microalbuminuria. Antihypertensive therapy and improved glycaemic control were independent predictors for remission.     

Blood pressure, antihypertensive treatment, and graft survival in kidney transplant patients

Whether the use of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker inhibitor (ACEI/ARB) is beneficial in renal transplant recipients remains controversial. In this retrospective study on 505 renal transplant recipients, we analyzed blood pressure and graft survival according to antihypertensive treatment with ACE-I/ARB and/or calcium channel blockers (CCB) over a period of 10 years. Patients were stratified according to their blood pressure 1 year after transplantation [controlled (≤130/80 mmHg; CTR, 181 patients) and noncontrolled (>130/80 mmHg; non-CTR, 324 patients)] and according to antihypertensive treatment (ACE-I/ARB and/or CCB taken for at least 2 years). One year after transplantation, 88.4% of CTR and 96.6% of non-CTR received antihypertensive treatment ( P  < 0.05). Graft survival was longer in CTR than in non-CTR ( P  < 0.05). Importantly, graft survival was longer in patients who received long-term treatment with ACEI/ARB, CCB, or a combination of ACEI/ARB and CCB ( P  < 0.001). The beneficial effect of ACEI/ARB therapy was more pronounced in non-CTR compared with that of CTR. We conclude that blood pressure control is a key target for long-term graft survival in renal transplant patients. Long-term ACEI/ARB and CCB therapy is beneficial for graft survival, especially in patients with diabetes and/or albuminuria.     

No impact of hyperkalaemia with renin-angiotensin system blockades in maintenance haemodialysis patients.

BACKGROUND: Renin-angiotensin system (RAS) blockades, angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are well accepted for the cardiorenal-protective benefits added to antihypertensive effects in chronic kidney diseases (CKD), but associated with an increased risk of hyperkalaemia. However, few studies have investigated the effect of RAS blockades on serum potassium in dialysis patients. METHODS: Hyperkalaemia associated with RAS blockades by ACEI and/or ARB was evaluated in 69 patients on maintenance haemodialysis, who underwent a three-period crossover study in four groups (no exposure to RAS blockades, ACEI or ARB alone and ACEI plus ARB treatments), lasting one month in each period. RESULTS: Sixty-two patients completed this prospective 3-month study, and no one stopped the study because of the development of hyperkalaemia and/or complications. Mean serum K was similar among the four periods (no exposure, 5.54+/-0.67 mmol/l; ACEI alone, 5.54+/-0.75 mmol/l; ARB alone, 5.50+/-0.66 mmol/l; ACEI+ARB combination, 5.42+/-0.66 mmol/l) and was also equal when compared between the two groups with and without exposure to RAS blockades (5.48+/-0.68 vs 5.54+/-0.67 mmol/l, P=NS). The incidence of severe hyperkalaemic episodes (>6.0 mmol/l) upon monthly predialysis serum K determination was 25.8% with no exposure to RAS blockades, 29.8% for ACEI alone, 19.6% for ARB alone and 17.7% for ACEI+ARB combination without statistically significant differences among the four periods (P=NS). Among covariables, the degree of Kt/V, intakes of other medications interfering with potassium homeostasis and diabetes mellitus did not result in any significant hyperkalaemic changes during the 3-month study period except anuric patients compared with non-anuric patients (5.58+/-0.69 vs 5.19+/-0.65 mmol/l, P<0.001). CONCLUSION: Neither monotherapy (ACEI or ARB) nor combination therapy (ACEI plus ARB) is associated with the additional risk of hyperkalaemia in patients on maintenance haemodialysis. However, those patients with anuria on RAS blockades warrant the cautious monitoring of serum K to prevent hyperkalaemia.     

Time course of the antiproteinuric and antihypertensive effect of losartan in diabetic nephropathy.

BACKGROUND: Blockade of the renin-angiotensin system is the primary target in the treatment of diabetic kidney disease. Angiotensin II subtype 1 (AT1) receptor antagonists reduce albuminuria and lower blood pressure, but the initial time course of these effects after initiation of treatment is unknown. We evaluated the time course of the antihypertensive and antialbuminuric effect after initiation of AT1 receptor blockade by losartan in diabetic nephropathy. METHODS: Ten hypertensive type 1 diabetic patients with diabetic nephropathy were included in the study. After a washout period of 4 weeks, patients received losartan 100 mg once daily for 28 days. Every morning, one urine sample was collected for daily determination of albumin/creatinine ratio. Twenty-four hour blood pressure (Takeda TM2420), plasma renin and plasma creatinine were measured at baseline and days 7, 14 and 28. RESULTS: Baseline levels of urinary albumin/creatinine ratio and 24 h mean arterial blood pressure were 676 (402-1136) mg/g (geometric mean and 95% CI, respectively) and 100+/-3 mmHg (mean +/- SEM). Albumin/creatinine ratio was significantly reduced after 7 days of treatment by 29% (15-41) (95% CI) without significant further reductions during the 28 day study period (P<0.01 vs baseline). Mean arterial blood pressure was significantly lowered by 7 mmHg after 7 days of treatment and remained unchanged throughout the study (P<0.01 vs baseline). Plasma renin was significantly increased from baseline after initiation of losartan treatment and stabilized after 7 days (P<0.01). We found no changes in plasma creatinine during the study. CONCLUSIONS: The initial time course of the reduction in arterial blood pressure and albuminuria are concordant, which suggests that systemic and renal haemodynamic mechanisms are of primary importance in the reduction of albuminuria.     

Renoprotective effects of angiotensin II receptor blockade in type 1 diabetic patients with diabetic nephropathy

BACKGROUND: Angiotensin I-converting enzyme (ACE) inhibitors reduce angiotensin II formation and induce bradykinin accumulation. Animal studies suggest that bradykinin may play a role for the effects of ACE inhibition on blood pressure and kidney function. Therefore, we compared the renal and hemodynamic effects of specific intervention in the renin-angiotensin system by blockade of the angiotensin II subtype-1 receptor to the effect of ACE inhibition. METHODS: A randomized, double-blind, cross-over trial was performed in 16 type 1 diabetic patients (10 men), age 42 +/- 2 years (mean +/- SEM). The study consisted of five periods, each lasting two months. The patients received losartan 50 mg, losartan 100 mg, enalapril 10 mg, enalapril 20 mg, and placebo in random order. At the end of each period, albuminuria, 24-hour blood pressure, and glomerular filtration rate (GFR) were determined. RESULTS: Both doses of losartan and enalapril reduced albuminuria (P < 0.05) and mean arterial blood pressure (MABP; P < 0.05), whereas GFR remained stable. Albuminuria was reduced by 33% (95% CI, 12 to 51) on losartan 50 mg, 44% (95% CI, 26 to 57) on losartan 100 mg, 45% (95% CI, 23 to 61) on enalapril 10 mg, and 59% (95% CI, 39 to 72) on enalapril 20 mg, and MABP fell by 9 +/- 2, 8 +/- 2, 6 +/- 3, and 11 +/- 3 mm Hg (mean +/- SEM), respectively. No significant differences were found between the effects of losartan 100 mg and enalapril 20 mg. HbA1C and sodium intake remained unchanged throughout the study, whereas a significant rise in serum potassium occurred during ACE inhibition. CONCLUSION: The angiotensin II subtype 1 receptor antagonist, losartan, reduces albuminuria and MABP similar to the effect of ACE inhibition. These results indicate that the reduction in albuminuria and blood pressure during ACE inhibition is primarily caused by interference in the renin-angiotensin system. Our study suggest that losartan represents a valuable new drug in the treatment of hypertension and proteinuria in type 1 diabetic patients with diabetic nephropathy.     

Enhanced renoprotective effects of ultrahigh doses of irbesartan in patients with type 2 diabetes and microalbuminuria

BACKGROUND: The purpose of this study was to evaluate the renoprotective effect as reflected by short-term changes in albuminuria of ultrahigh doses of irbesartan in type 2 diabetic patients with microalbuminuria. METHODS: This double-masked randomized crossover trial included 52 (41 males) hypertensive type 2 diabetic patients with microalbuminuria on ongoing antihypertensive medication. At inclusion, previous antihypertensive treatment was discontinued and replaced with bendroflumethiazide, 5 mg once daily, for the entire study. Following 2 months wash-out (baseline), patients were treated randomly with irbesartan 300, 600, and 900 mg once daily, each dose for 2 months. End points evaluated at the end of each study period included urinary albumin excretion rate (UAE) (mean of three 24-hour collections), 24-hour ambulatory blood pressure, and glomerular filtration rate (GFR) [chromium 51 ethylenediaminetetraacetic acid (51Cr-EDTA)]. RESULTS: Baseline values were: 24-hour UAE [geometric mean (95% CI)] 134 (103 to 170) mg/24 hours, ambulatory blood pressure [mean (SD)] 140 (10)/77 (7) mm Hg, and GFR 103 (19) mL/min/1.73 m2. All doses of irbesartan significantly reduced UAE, ambulatory blood pressure, and GFR from baseline. Reductions in UAE from baseline were 52% (46% to 57%), 49% (43% to 54%), and 59% (54% to 63%) with increasing doses of irbesartan (P < 0.01). UAE was reduced significantly more by irbesartan 900 mg compared with lower doses with an additional reduction in UAE of 15% (2% to 26%) by irbesartan 900 mg compared with 300 mg (P = 0.02). The greater reduction in albuminuria by irbesartan 900 vs. 300 mg was more pronounced in patients with UAE during irbesartan 300 mg above vs. below the median [31% (18% to 42%) vs. -9% (-25% to 6%), respectively (P < 0.05)]. With increasing doses systolic ambulatory blood pressure was reduced from baseline by 8 (4 to 12), 9 (5 to 13), and 9 (5 to13) mm Hg, and diastolic ambulatory blood pressure by 6 (4 to 7), 7 (6 to 9), and 7 (6 to 9) mm Hg (NS between doses). CONCLUSION: Ultrahigh dosing of irbesartan (900 mg once daily) is generally safe and offers additional renoprotection independent of changes in systemic blood pressure and GFR in comparison to the currently recommended dose of 300 mg.     

Dual blockade of the rennin–angiotensin system versus maximal recommended dose of angiotensin II receptor blockade in chronic glomerulonephritis

Background Proteinuria and hypertension are predictors of poor renal outcome in chronic glomerulonephritis (CGN). At the same level of blood pressure (BP) control, we evaluated which is superior, dual blockade of the rennin–angiotensin system (RAS) with both angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II type 1 (AT-1) receptor blockade (ARB) or single blockade of ARB to reduce proteinuria and to preserve renal function in patients with CGN. Methods In this prospective, parallel, open study of 86 patients with CGN, we compared the effects on proteinuria and renal functions of 36 months with comparable blood pressure (BP) control achieved by candesartan cilexetil (candesartan, 4–12 mg/day) or benazepril hydrochrolide (benazepril, 2.5–10 mg/day) with candesartan (4 mg/day). Aiming at BP 125/75 mmHg or less, the dose of candesartan (single blockade) or benazepril (dual blockade) was increased. Results Dual blockade decreased proteinuria more than single blockade with ARB (−42.3 vs. −60.5%, P < 0.01). Renal plasma flow (RPF) and glomerular filtration fraction (GFR) did not change significantly in either group. The filtration fraction (FF) decreased dual blockade more than single blockade (−1.7 vs. −19.0%, P < 0.05). Decreased FF was associated with the reduction of proteinuria (P < 0.05). Six percent of patients with dual blockade were not able to continue the study because of a dry cough. Conclusion Long-term dual blockade decreased proteinuria more than single blockade with ARB. Although ARB and ACEI have a glomerular size-selective function for proteinuria, a greater antiproteinuric effect may depend on renal hemodynamics, especially FF. Increased levels of bradykinin after ACEI can decrease FF and ameliorate proteinuria. Dry cough is a significant adverse effect of ACE inhibitor.     

Lowering of proteinuria in response to antihypertensive therapy predicts improved renal function in late but not in early diabetic nephropathy: a pooled analysis

In late diabetic nephropathy (DN) the initial lowering of albumin excretion rate (AER) with antihypertensive therapy is proportional to the degree of subsequent preservation of glomerular filtration rate (GFR). Whether a similar relationship exists between AER and GFR in early diabetes is not known. The present analysis has compared AER and GFR responses to antihypertensive therapy in 33 published studies (77 treatment groups) of early and late DN in type 1 (T1) and type 2 (T2) diabetes, analyzed on an intention-to-treat basis. Prospective trials were included if the initial change in AER during the first year of therapy and the change in GFR during at least 2 years of follow-up could be estimated from group mean data. The initial % decreases in AER were 5.9 +/- 4.3 (T1), 10.5 +/- 5.4 (T2, normotensive) and 18.4 +/- 6.2 (T2, hypertensive) in early DN and 7.6 +/- 11.1 (T1) and 20.8 +/- 5.5 (T2) in late DN. The corresponding annual % rates of decline of GFR were 2.0 +/- 0.5 (T1), 1.6 +/- 0.5 (T2, normotensive) and 2.1 +/- 0.3 (T2, hypertensive) in early DN and 9.8 +/- 1.5 (T1) and 9.2 +/- 1.1 (T2) in late DN. AER and GFR responses in each treatment group were closely correlated in late nephropathy (T1, r = -0.67, p = 0.03; T2, r = 0.57, p = 0.02) but not in early nephropathy. In contrast to late DN, the initial decrease in AER with antihypertensive therapy was not shown to predict the subsequent rate of decline of GFR in early DN. It follows that assessment of renoprotection during antihypertensive therapy in early nephropathy should be based not only on albuminuria but also on the GFR response.     

A PC-1 amino acid variant (K121Q) is associated with faster progression of renal disease in patients with type 1 diabetes and albuminuria

Insulin resistance characterizes type 1 diabetes in patients with albuminuria. A PC-1 glycoprotein amino acid variant, K121Q, is associated with insulin resistance. We examined the impact of the PC-1 K121Q variant on the rate of decline of the glomerular filtration rate (GFR) by creatinine clearance derived from the Cockroft-Gault formula in 77 type 1 diabetic patients with albuminuria who were followed for an average of 6.5 years (range 2.5-15). Patients carrying the Q allele (n = 22; 20 with KQ and 2 with QQ genotypes) had a faster GFR decline than those patients with the KK genotype (n = 55) (median 7.2 vs. 3.7 ml x min(-1) x year(-1); range 0.16 to 16.6 vs. -3.8 to 16.0 ml x min(-1) x year(-1); P < 0.001). Significantly more patients carrying the Q allele belonged to the highest tertile of GFR decline (odds ratio = 5.7, 95% CI 4.1-7.2, P = 0.02). Levels of blood pressure, HbA1c, and albuminuria were comparable in the two genotype groups. Albuminuria (P = 0.001), mean blood pressure (P = 0.046), and PC-1 genotype (P = 0.036) independently correlated with GFR decline. Because all patients were receiving antihypertensive treatment, the faster GFR decline in the patients carrying the Q allele could be the result of reduced sensitivity to the renoprotective effect of antihypertensive therapy. PC-1 genotyping identifies type 1 diabetic patients with a faster progression of diabetic nephropathy.     

Angiotensin converting enzyme inhibitor use soon after renal transplantation: a randomized, double-blinded placebo-controlled safety study

Activation of the renin-angiotensin system (RAS) followed by increased inflammatory cytokines may be important in the pathogenesis of chronic allograft dysfunction. As many renal transplant recipients show chronic changes on biopsy within the first year, early RAS blockade with angiotensin converting enzyme inhibitor (ACEI) could be beneficial. However, it remains unclear that early ACEI use is safe. We conducted a prospective, randomized, placebo-controlled trial to assess the safety of enalapril 5 mg during the early post-transplant period. Subjects took the study medication for six months. Primary endpoints were serum potassium (K) >5.9 mEq/L and 30% increase in baseline creatinine. A total of 53 subjects were randomized, and of them, 27 received the study drug. Twenty-nine subjects, 14 ACEI and 15 controls, completed the six-month protocol without reaching an endpoint. Patients on ACEI had higher K and higher BUN at six months. Serum creatinine, hematocrit, and urinary protein were not different. There was no difference in urinary TGF-β1. Twenty-four subjects reached study endpoints. When the common clinical endpoints of elevated creatinine and hyperkalemia were combined, ACEI group had significantly increased endpoints vs. control (10/13, 77% vs. 5/11, 45%, p < 0.05). We conclude that ACEI use in the early post-transplant period can be safe but patients must be carefully selected and monitored for elevations in serum creatinine and potassium. Whether early ACEI is beneficial in preserving allograft function requires further study.     

Reduction of urinary connective tissue growth factor by Losartan in type 1 patients with diabetic nephropathy

BACKGROUND: Connective tissue growth factor (CTGF) is an important profibrotic cytokine implicated in development of diabetic glomerulosclerosis. Urinary CTGF is reported to be significantly increased in patients with diabetic nephropathy. The present study aimed to investigate the short- and long term effects of angiotensin II receptor blockade by Losartan on urinary CTGF levels in hypertensive type 1 diabetic patients with diabetic nephropathy. METHODS: Seventy-one hypertensive type 1 diabetic patients with diabetic nephropathy were included in the study. After a washout period of 4 weeks, the patients received Losartan 50 mg, 100 mg, and 150 mg once daily in treatment periods each lasting 2 months. Thereafter, patients were followed prospectively during treatment with Losartan 100 mg o.d. with a total mean follow-up time of 36 months. At baseline, after 2, 4, and 6 months and then biannually, urinary and plasma CTGF levels [enzyme linked immunosorbent assay (ELISA) fibroGen], albuminuria (Turbidimetry), glomerular filtration rate (GFR) [51-creatinine ethylenediaminetetraacetic acid ((51)Cr-EDTA plasma clearance)] and 24 hours blood pressure (TM2420)) were determined. RESULTS: Baseline levels of urinary and plasma CTGF were 7076 (5708 to 8770) ng/24 hours [geometric mean (95% CI)] and 12.7 (7.3) ng/mL [mean (SD)], respectively. Albuminuria, GFR, and arterial blood pressure at baseline were 1152 (937 to 1416) mg/24 hours, 88 (24) mL/min/1.73 m(2), and 153/80 (17/9) mm Hg, respectively. Losartan significantly reduced urinary CTGF by 21% (9 to 31) (95% CI) initially (P < 0.05 vs. baseline), with no further reduction after increasing dose. The sustained reduction in urinary CTGF was 22% (12 to 32) (P < 0.05 vs. baseline). Rate of decline in GFR during the study was 3.2 (-1.6 to 15.9) mL/min/year [median (range)]. Reduction in urinary CTGF was correlated with a lower rate of decline in GFR (r= 0.23, P= 0.05). Plasma CTGF remained unchanged throughout the study. CONCLUSION: Our 3-year study demonstrates that Losartan persistently reduces urinary CTGF excretion, which is associated with a slower rate of decline in GFR.     

Management of hypertension in chronic kidney disease: the Italian multicentric study

BACKGROUND: Guidelines have indicated the achievement of blood pressure target (BP <130/80 mmHg) as a priority in the conservative treatment of chronic kidney disease (CKD), but the current implementation of these recommendations in clinical practice is unknown. METHODS: We assessed control rates, treatment and clinical correlates of hypertension in 1201 adult non-dialyzed CKD patients followed up by a nephrologist for at least 6 months. RESULTS: Estimated glomerular filtration rate (GFR) was 32 (SD 15) mL/min/1.73 m2. BP target was not achieved in 88% of patients (95% confidence interval (95% CI): 86-90%). In 84% of patients, BP levels were also above the target at the first visit to the nephrology unit 4.5 yrs previously. The risk of not achieving BP target during the nephro-logy follow-up was associated with older age (odds ratio (OR): 1.24, 95% CI 1.06-1.45, p=0.008), diabetes (OR: 2.25, 95% CI 1.20-4.20, p=0.011), and the duration of hypertension (OR: 1.13, 95% CI 1.02-1.24, p=0.016). Among patients with uncontrolled BP, about 70% received multidrug antihypertensive therapy including renin-angiotensin system (RAS) inhibitors; conversely, diuretic treatment was prescribed in a minority of patients (37%), and at insufficient doses in half the cases, despite the insufficient implementation of a low salt diet (18%). CONCLUSIONS: BP target was not reached in most CKD patients routinely seen in the renal clinics. The main barrier to guideline implementation is possibly the inadequate treatment of extracellular volume expansion despite the large prevalence of factors, such as older age and diabetes, which further enhance the intrinsic BP salt sensitivity of CKD.     

ACE-inhibitor or AT2-antagonist therapy of renal transplant recipients is associated with an increase in serum potassium concentrations.

BACKGROUND: Angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II type 1 receptor blockers (ARB) are frequently prescribed to renal transplant recipients with a reduced glomerular filtration rate (GFR). The aim of this study was to investigate the association of ACEI/ARB use and serum potassium levels in renal graft recipients. METHODS: We conducted an open cohort study of 2041 first renal allograft recipients, transplanted at the Medical University of Vienna between 1990 and 2003. Serum potassium levels were compared over an up to 10 years of observation period between subjects with versus without ACEI/ARB therapy using a mixed effects general linear model. The analysis was adjusted for several covariables known to influence serum potassium such as the use of diuretics, beta blockers, calcineurin inhibitor (CNI) based immunosuppression, estimated GFR, time since renal transplantation, diabetes, years on dialysis and recipient age. RESULTS: The overall adjusted estimated serum potassium difference between recipients with versus without ACEI/ARB therapy was 0.08 mmol/l (P < 0.001). The use of diuretics was associated with a 0.11 mmol/l (P < 0.001) lower potassium concentration whereas each GFR decrease by 10 ml/min led to an increase of 0.04 mmol/l (P < 0.001). CNI intake increased serum potassium by 0.06 mmol/l (P = 0.002). Furthermore, serum potassium increased by 0.17 mmol/l within the first decade after transplantation (P < 0.001) while holding the other covariables constant. No effect modification between ACEI/ARB and time since transplantation was observed. Nineteen subjects (2.4%) discontinued the ACEI/ARB therapy due to hyperkalaemia. CONCLUSIONS: In summary, relevant hyperkalaemia associated with ACEI/ARB therapy is negligible in renal transplant recipients during long-term follow-up. The hyperkalaemic effect of ACEI/ARB is balanced by the use of diuretics.     

Effect of low-dose dual blockade of renin-angiotensin system on urinary TGF-beta in type 2 diabetic patients with advanced kidney disease.

BACKGROUND: We evaluated the renoprotective effects of dual blockade of renin-angiotensin system (RAS) by using a low-dose combination of ACE inhibiter and angiotensin II receptor blocker in type 2 diabetic patients with advanced kidney disease. The amount of proteinuria and the urinary levels of bioassayable TGF-beta1 were used as surrogate markers of renal injury and sclerosis. METHODS: We performed a prospective double-blinded randomized crossover trial consisting of three 16-week treatment periods with ramipril alone (10 mg/day), candesartan alone (16 mg/day), and ramipril (5 mg/day) plus candesartan (8 mg/day) combination therapy. Twenty-one type 2 diabetic patients with overt nephropathy with a 24 h urinary protein excretion rate (UPER) of > 1.0 g/24 h and creatinine clearance (Ccr) of 30 to 59 ml/min/1.73 m2 completed the entire study. RESULTS: Subjects consisted of 10 female and 11 male patients with a mean age of 49 +/- 8 years and duration of diabetes ranging from 4 to 13 years. At baseline, 24-h blood pressures (BPs) were 133 +/- 6/81 +/- 7 mmHg, Ccr 40.6 +/- 4.1 ml/min/1.73 m2, 24-h UPER 4.1 +/- 1.9 g/24 h, and urinary TGF-beta1 level 28.4 +/- 16.1 pg/mg creatinine (cr). Although there was no comparable change in BP and plasma/urinary biochemical parameters, 24-h UPER was significantly reduced by the combination therapy (2.9 +/- 1.4 g/24 h) compared with that of ramipril (3.5 +/- 1.8 g/24 h) and of candesartan (3.3 +/- 2.0 g/24 h) single therapy (P < 0.05). Urinary TGF-beta1 level was reduced in all three therapies compared with that of the control (28.4 +/- 16.1 pg/mg cr) (P < 0.05). However, the combination therapy showed the most significant change (combination 19.6 +/- 10.6 pg/mg cr; ramipril 24.7 +/- 13.3 pg/mg cr; candesartan; 23.4 +/- 11.7 pg/mg cr). No significant or irreversible adverse effect was observed in the 21 patients who completed the entire study. CONCLUSIONS: The dual blockade of RAS with low-dose ramipril plus candesartan was found to be safe and offered additive benefits with respect to reducing proteinuria and urinary TGF-beta1 excretion in diabetic patients with advanced kidney disease. These benefits were evident as compared with single ramipril and candesartan therapies at doses two-fold greater. Further study on the dose-titration is mandatory in terms of safety and especially for maximizing renoprotection in this patient population.