Association of angiotensin I-converting enzyme gene polymorphism with susceptibility to antiproteinuric effect of angiotensin I-converting enzyme inhibitors in patients with proteinuria

ACE insertion/deletion polymorphism and diabetic nephropathy: clinical implications of genetic information

Approximately 20-40% of diabetic patients develop nephropathy which is the leading cause of ESRD in developed countries. The ACE I/D polymorphism is thought to be a marker for functional polymorphism which regulates circulating and tissue ACE activity. While the initial study found a protective effect of the II genotype on the development of nephropathy in IDDM patients, subsequent studies have addressed the role of ACE I/D polymorphism in the development and progression of diabetic nephropathy. RAAS blockers are the first line drugs for the treatment hypertension associated with diabetes and have been widely used in everyday clinical practice for the purpose of reducing proteinuria in patients with various renal diseases. However, the antiproteinuric effect of RAAS blockers is variable and the percentage of reducing proteinuria is in the range of 20-80%. The antiproteinuric effect of RAAS blockers may be related to a number of factors: the type or the dose of RAAS blockers, the duration of therapy, the level of sodium intake, and the type of patient's ACE I/D genotype. Besides the nongenetic factors, drug responses, can be influenced by ACE gene polymorphism. In this review, we discuss the relationship between ACE I/D polymorphism and diabetic nephropathy and therapeutic response of RAAS blockers.

Genomics and Disease Progression in IgA Nephritis

Apart from clinical, histological and biochemical indices, genomics are now being employed to unravel the pathogenetic mechanisms in the disease progression of IgA nephritis (IgAN). The results of angiotensin converting enzyme (ACE) gene polymorphism have been controversial. Those patients with the DD genotype seem to have a poorer prognosis. However, with high dose angiotensin receptor blocker (ARB) therapy, the ACE gene polymorphism status of a patient may no longer be a matter for concern as those with the DD genotype would also respond favourably to high dose ARB therapy. Association studies with gene sequencing and haplotypes have suggested that multiple genes are involved in the pathogenesis of IgAN. Some workers have reported a synergistic effect in the combined analysis of AGT-M235T and ACE I/D polymorphism. With the use of deoxyribo nucleic acid (DNA) microarray, tens of thousands of gene expressions genome-wide can be examined together simultaneously. A locus of familial IgAN has been described with strong evidence of linkage to IgAN1 on chromosome 6q22-23. Two other loci were reported at 4q26-31 and 17q12-22. DNA microarray techniques could also help in the identification of specific pathogenic genes that are up- or down-regulated and this may allow genome wide analyses of these genes and their role in the pathogenesis and progression of IgAN. Recently, using genome-wide association studies (GWAS) more loci for disease susceptibility for IgAN have been identified at 17p13, 8p23, 22q12, 1q32 and 6p21. Key words: Gene sequencing, Haplotypes, Microarray, Single nucleotide polymorphism

The insertion/deletion polymorphism of the angiotensin-converting enzyme gene is associated with progression, but not development, of albuminuria in Iranian patients with type 2 diabetes

INTRODUCTION

The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene has been shown to be associated with a number of complications of type 2 diabetes.

RESULTS

on the development and progression of albuminuria, however, have remained controversial, with ethnic differences being a potential reason.The present study is the first report to examine Iranian patients.

METHODS

Patients (322; 162 males) with type 2 diabetes were categorised in this cross-sectional study into the following groups: normoalbuminuria (n=145), microalbuminuria (n=129) and macroalbuminuria (n=48).ACE gen I/D polymorphism genotypes were determined using the polymerase chain reaction method.

RESULT

s. The distribution of ACE genotypes was significantly different among the groups (p<0.001), with the II genotype decreasing and the DD genotype increasing in frequency with increasing severity of albuminuria. Multivariate regression analysis showed that the ACE genotype did not change the odds of having microalbuminuria versus normoalbuminuria, while the D allele independently increased the odds of having macroalbuminuria versus microalbuminuria approximately threefold (p<0.01).

CONCLUSIONS

In Iranian patients with type 2 diabetes, the D allele is associated with progression, but not development, of albuminuria.

Significance of genetic polymorphisms of the renin–angiotensin–aldosterone system in cardiovascular and renal disease

The angiotensin converting enzyme (ACE) is a component of the renin–angiotensin–aldosterone system (RAAS). The RAAS – involved primarily in blood pressure and sodium homeostasis – is activated in many renal and cardiovascular diseases, and therapy with ACE inhibitors and other blockers of the RAAS has proven to be clinically beneficial. Plasma and tissue levels of ACE are at least partially determined by a genetic polymorphism based on the presence (insertion [I]) or absence (deletion [D]) of a 287 base pair element in intron 16. In particular Asian subjects with the DD genotype (and increased ACE activity) have been reported to be at higher risk for cardiovascular disorders and nephropathy. Numerous studies evaluated the role of the ACE I/D polymorphism as well as other genetic variants of the RAAS in the context of RAAS inhibitor therapy. However, as race and environmental factors, such as salt intake also affect treatment response most studies were underpowered leading to conflicting results.

Angiotensin converting enzyme insertion/deletion polymorphism and renoprotection in diabetic and nondiabetic nephropathies

Despite the huge amount of studies looking for candidate genes, the ACE gene remains the unique, well-characterized locus clearly associated with pathogenesis and progression of chronic kidney disease, and with response to treatment with drugs that directly interfere with the renin angiotensin system (RAS), such as angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists (ARA). The II genotype is protective against development and progression of type I and type II nephropathy and is associated with a slower progression of nondiabetic proteinuric kidney disease. ACE inhibitors are particularly effective at the stage of normoalbuminuria or microalbuminuria in both type I and type II diabetics with the II genotype, whereas the DD genotype is associated with a better response to ARA therapy in overt nephropathy of type II diabetes and to ACE inhibitors in male patients with nondiabetic proteinuric nephropathies. The role of other RAS or non-RAS polymorphisms and their possible interactions with different ACE I/D genotypes are less clearly defined. Thus, evaluating the ACE I/D polymorphism is a reliable tool to identify patients at risk and those who may benefit the most of renoprotective therapy with ACE inhibitors or ARA. This may guide pharmacologic therapy in individual patients and help design clinical trials in progressive nephropathies. Moreover, it might help optimize prevention and intervention strategies at population levels, in particular, in countries where resources are extremely limited and 1 million patients continue to die every year of cardiovascular or renal disease.

Angiotensin I-converting enzyme insertion-related genotypes and allele are associated with higher susceptibility of endometriosis and leiomyoma

Endometriosis and leiomyoma display features similar to malignancy, requiring neovascularization to proliferation and growth. Altered vascular-related genes might be related to the development of endometriosis and leiomyoma. Polymorphisms of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) genes have been linked with some vascular diseases. This study investigates whether ACE I/D gene polymorphisms could be used as markers of susceptibility in endometriosis and leiomyoma. Women were divided into three groups: (1) endometriosis (n = 125); (2) leiomyoma (n = 120); (3) normal controls (n = 128). Genomic DNA was obtained from peripheral leukocyte. ACE I/D gene polymorphisms in intron 16 were amplified by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) Genotypes and allelic frequencies in both groups were compared. We observed the genotype distribution and allele frequency of ACE I/D gene polymorphisms in both groups were significantly different. Proportions of ACE*I homozygote/heterozygote/D homozygote in both groups were: (1) 50.4/24/25.6%; (2) 25/23.33/51.67%; (3) 10.2/29.7/60.1%. Proportions of I/D alleles in each group were: (1) 62.4/37.6%; (2) 36.7/63.3%; (3) 25/75%. We concluded that ACE*I/D gene polymorphisms are associated with endometriosis and leiomyoma susceptibilities. ACE*I-related genotypes and allele are strongly related to the occurrence of endometriosis and moderately related to the occurrence of leiomyoma.

ACE phenotyping as a first step toward personalized medicine for ACE inhibitors. Why does ACE genotyping not predict the therapeutic efficacy of ACE inhibition?

Angiotensin (Ang)-converting enzyme (ACE) inhibitors are widely used for the treatment of cardiovascular diseases. Not all patients respond to ACE inhibitors, and it has been suggested that genetic variation might be a useful marker to predict the therapeutic efficacy of these drugs. In particular, the ACE insertion (I)/deletion (D) polymorphism has been investigated in this regard. Despite a decade of intensive research involving the genotyping of thousands of patients, we still do not know whether ACE genotyping helps in predicting the success of ACE inhibition. This review critically addresses the concept that predictive information on therapeutic efficacy of ACE inhibitors might be obtained based on ACE genotyping. It answers the following questions: Do higher ACE levels really result in higher Ang II levels? Is ACE the only converting enzyme in humans? Does ACE inhibition affect ACE expression? Why does ACE have 2 catalytically active domains? What is the relevance of ACE inhibitor-induced signaling through membrane-bound ACE? The review ends with the proposal that ACE phenotyping may prove to be a better first step toward personalized medicine for ACE inhibitors than ACE genotyping.

Antiproteinuric effect of losartan in non-diabetic renal disease is not dependent on ACE insertion/deletion polymorphism

BACKGROUND

The antiproteinuric effect of angiotensin-converting enzyme (ACE) inhibitors appears to vary depending on the ACE insertion (I)/deletion (D) genotype in non-diabetic nephropathy. This interaction may be overcome by using an angiotensin II receptor blocker. We evaluated the short-term antiproteinuric effect of losartan according to the ACE I/D genotype in patients with non-diabetic proteinuric renal diseases.

METHODS

Ninety-nine (II/ID/DD: 36/52/11) non-diabetic patients with overt proteinuria were enrolled. The patients received losartan 50 mg daily followed by 100 mg in two treatment periods each lasting 12 weeks. Clinical parameters including proteinuria were measured at baseline and at the end of each period.

RESULTS

At baseline each genotype (II/ID/DD) had comparable mean arterial blood pressure (mean +/- SD) 103.2 +/- 11.1/102.7 +/- 10.6/104.1 +/- 15.3; proteinuria (geometric mean, 95% CI, mg/day) 1,839 (1,518-2,227)/1,998 (1,683-2,372)/1,613 (1,072-2,427), and creatinine clearance (ml/min/1.73 m(2)) 65.7 +/- 28.4/63.2 +/- 27.8/68.8 +/- 25.3, respectively. Both doses of losartan significantly lowered blood pressure and proteinuria (p < 0.05 vs. baseline), and losartan 100 mg was more effective than 50 mg in reducing proteinuria (52.5 +/- 29.0 vs. 40.5 +/- 30.8%, respectively, p = 0.001). No differences in the antiproteinuric effect of losartan was observed among the ACE I/D genotype. Losartan 100 mg demonstrated a comparable degree of mean arterial pressure (mean +/- SD, %) (II/ID/DD, 13.3 +/- 7.6/10.8 +/- 9.8/13.0 +/- 11.6, respectively, p = NS) and proteinuria reduction (mean, 95% CI) among the three genotypes (51.4% (40.3-62.5%)/53.4% (45.5-61.4%)/51.4% (40.0-63.8%), respectively, p = NS).

CONCLUSION

Our data suggest that losartan provides a similar short-term antiproteinuric response for all three genotypes of ACE I/D genotype in non-diabetic proteinuric chronic renal disease.

Angiotensin-converting enzyme (ACE) inhibition in type 2, diabetic patients – interaction with ACE insertion/deletion polymorphism

Angiotensin-converting enzyme (ACE) insertion(I)/deletion (D) polymorphism may modify the effect of inhibition of the renin-angiotensin-aldosterone system (RAAS) on survival and cardiorenal outcomes in type 2, diabetes. A consecutive cohort of 2089 Chinese type 2 diabetic patients with mean (+/- standard deviation) age of 59.7 +/- 13.1 years were genotyped for this polymorphism by polymerase chain reaction method and were followed prospectively for a median period of 44.6 (interquartile range: 23.7, 57.5) months. Clinical outcomes, including all-cause mortality, cardiovascular and renal end points, were examined. The frequency for I allele was 67.1 and 32.9% for D allele, with observed genotype frequencies of 45.8, 42.6, and 11.6% for 3, DI and DD, respectively. ACE DD polymorphism was an independent predictor for renal end point with hazard ratio (HR) (95% confidence interval) of 1.72 (1.16, 2.56), but not for cardiovascular end point or mortality. After controlling for confounding factors, including ACE I/D genotype, the usage of RAAS inhibitors was associated with reduced risk of mortality (HR 0.34 (0.23, 0.50)) and renal end point (HR 0.55 (0.40, 0.75)). On subgroup analysis, the beneficial effects on survival (II vs DI vs DD: HR 0.29 (0.16, 0.51) vs 0.25 (0.14, 0.46) vs 1.33 (0.41, 4.31)) and renoprotection (II vs DI vs DD: 0.52 (0.30, 0.90) vs 0.43 (0.25, 0.72) vs 0.95 (0.43, 2.12)) were most evident in II and DI carriers. In conclusion, inhibition of RAAS was associated with reduced risk of mortality and occurrence of renal end point in Chinese type 2 diabetic patients. These benefits were most evident among II and DI carriers.

Pharmacogenetic association of the angiotensin-converting enzyme insertion/deletion polymorphism on blood pressure and cardiovascular risk in relation to antihypertensive treatment: the Genetics of Hypertension-Associated Treatment (GenHAT) study

BACKGROUND

Previous studies have reported that blood pressure response to antihypertensive medications is influenced by genetic variation in the renin-angiotensin-aldosterone system, but no clinical trails have tested whether the ACE insertion/deletion (I/D) polymorphism modifies the association between the type of medication and multiple cardiovascular and renal phenotypes.

METHODS AND RESULTS

We used a double-blind, active-controlled randomized trial of antihypertensive treatment that included hypertensives > or =55 years of age with > or =1 risk factor for cardiovascular disease. ACE I/D genotypes were determined in 37 939 participants randomized to chlorthalidone, amlodipine, lisinopril, or doxazosin treatments and followed up for 4 to 8 years. Primary outcomes included fatal coronary heart disease (CHD) and/or nonfatal myocardial infarction. Secondary outcomes included stroke, all-cause mortality, combined CHD, and combined cardiovascular disease. Fatal and nonfatal CHD occurred in 3096 individuals during follow-up. The hazard rates for fatal and nonfatal CHD and the secondary outcomes were similar across antihypertensive treatments. ACE I/D genotype group was not associated with fatal and nonfatal CHD (relative risk of DD versus ID and II, 0.99; 95% CI, 0.91 to 1.07) or any secondary outcome. The 6-year hazard rate for fatal and nonfatal CHD in the DD genotype group was not statistically different from the ID and II genotype group by type of treatment. No secondary outcome measure was statistically different across antihypertensive treatment and ACE I/D genotype strata.

CONCLUSIONS

ACE I/D genotype group was not a predictor of CHD, nor did it modify the response to antihypertensive treatment. We conclude that the ACE I/D polymorphism is not a useful marker to predict antihypertensive treatment response.

Drug-gene interactions between genetic polymorphisms and antihypertensive therapy

Genetic factors may influence the response to antihypertensive medication. A number of studies have investigated genetic polymorphisms as determinants of cardiovascular response to antihypertensive drug therapy. In most candidate gene studies, no such drug-gene interactions were found. However, there is observational evidence that hypertensive patients with the 460 W allele of the alpha-adducin gene have a lower risk of myocardial infarction and stroke when treated with diuretics compared with other antihypertensive therapies. With regard to blood pressure response, interactions were found between genetic polymorphisms for endothelial nitric oxide synthase and diuretics, the alpha-adducin gene and diuretics, the alpha-subunit of G protein and beta-adrenoceptor antagonists, and the ACE gene and angiotensin II type 1 (AT(1)) receptor antagonists. Other studies found an interaction between ACE inhibitors and the ACE insertion/deletion (I/D) polymorphism, which resulted in differences in AT(1) receptor mRNA expression, left ventricular hypertrophy and arterial stiffness between different genetic variants. Also, drug-gene interactions between calcium channel antagonists and ACE I/D polymorphism regarding arterial stiffness have been reported. Unfortunately, the quality of these studies is quite variable. Given the methodological problems, the results from the candidate gene studies are still inconclusive and further research is necessary.

Relationship between polymorphism of the angiotensin-converting enzyme gene and the response to angiotensin-converting enzyme inhibition in hypertensive patients

The aim of this study was to investigate the relationship between polymorphism of the anglotensin-converting enzyme (ACE) gene and the blood pressure response to ACE inhibition in a hypertensive cohort. Imidapril (5-10 mg/day) or benazepril (10-20 mg/day) was administered for 6 weeks to 517 essential hypertensives. ACE gene polymorphism was examined by the polymerase chain reaction (PCR) method and the patients were classified as having the 190-bp deletion homozygous (DD) genotype, the 490-bp insertion homozygous (II) genotype, or the 490-bp insertion, 190-bp deletion heterozygous (ID) genotype. The achieved change in systolic and diastolic blood pressure (SBP and DBP) was analyzed for association with genotypes at the ACE gene locus. The DD genotype was observed in 132 patients (25.5%), the ID genotype in 255 patients (49.3%), and the II genotype in 130 patients (25.2%). The SBP reductions in the patients with the DD genotype, II genotype, and ID genotype were -14.5 +/- 12.7 mmHg, -14.3 +/- 13.1 mmHg and -14.0 +/- 12.2 mmHg, respectively (p = 0.94). The DBP reductions in the patients with the DD genotype, II genotype, and ID genotype were -8.7 +/- 7.4 mmHg, -8.7 +/- 7.7 mmHg and -8.5 +/- 6.7 mmHg, respectively (p = 0.96). There was no significant association between the ACE gene polymorphisms and the response to ACE inhibition. These results suggest that ACE genotype does not predict the blood pressure-lowering response to antihypertensive treatment with ACE inhibition.

Comparison of histopathological characteristics of allograft biopsy between responder and non-responder to antiproteinuric effect of angiotensin-converting enzyme inhibitor (ACEI)

Angiotensin-converting enzyme inhibitor (ACEI) has become recognized as agents that have renoprotective effects in the treatment of progressive renal diseases including post-transplant kidneys. Previously we demonstrated the safety and effectiveness of ACEI treatment on the hypertensive proteinuric post-transplant patients (N = 10) who had been followed up for 12 months. However, not all patients show good response in urinary protein reduction. We aimed to analyse the histopathological factor(s) affecting the responsiveness of proteinuria to ACEI treatment. Fourteen post-transplant patients with proteinuria who were treated with ACEI and underwent allograft biopsy were analysed. Eight patients showed 50% or more reduction in proteinuria (responder). The other 6 patients showed less (< 50%) reduction in proteinuria (non-responder). There was no difference in clinical characteristics (BP, renal function, donor age, recipient body mass index), dietary sodium or protein intake, and diuretic use between the two groups. As a histopathological characteristic, glomerular size in responder group was significantly larger than that in non-responder group. This suggests that the large glomerular size at least partly contributes to the responsiveness in urinary protein reduction to ACEI treatment in kidney allograft recipients with proteinuria.

Angiotensinogen gene variation and renoprotective efficacy of renin-angiotensin system blockade in IgA nephropathy

BACKGROUND

Blockade of the renin-angiotensin system (RAS) is well documented to be renoprotective; however, not all patients with glomerulonephritis respond well to this therapy. The interindividual variation in response to the RAS blockade may be in part genetically determined, whereas the results have been controversial.

METHODS

We investigated whether the therapeutic efficacy of angiotensin-converting enzyme (ACE) inhibitors and/or angiotensin receptor blocker on renal prognosis is modified by the angiotensinogen gene (AGT) polymorphism in immunoglobulin A nephropathy (IgAN). In total, 259 patients with histologically proven IgAN were analyzed for clinical manifestations, renal survival, and their associations with AGT A(-20)C and M235T.

RESULTS

The renal prognosis of 110 patients, who received ACE inhibitors/angiotensin receptor blocker during their clinical course, was significantly better than those without ACE inhibitors/angiotensin receptor blockers despite higher blood pressures and heavier proteinuria. The Cox proportional hazards regression model showed an increased hazard ratio (HR) for urinary protein (more than 1.0 g/day) of 3.346 (P = 0.0001), hypertension of 1.949 (P = 0.01), deteriorated renal function of 3.040 (P < 0.0001), no ACE inhibitor/angiotensin receptor blocker administration of 2.725 (P = 0.0004), and the T235 and C(-20) haplotype of 1.608 (P = 0.0322). Only in patients carrying at least one M235 and A(-20) haplotype did the administration of ACE inhibitors/angiotensin receptor blockers have no significant effect on the prognosis of renal function (Kaplan-Meier, log rank test, chi2 = 0.700; P = 0.4028), whereas it was significant in patients who had other haplotypes of AGT (chi2 = 11.805; P = 0.0006).

CONCLUSION

This study provides evidence that the M235T and A(-20)C genotype of AGT can influence the therapeutic efficacy of a RAS blockade on the renal survival in IgAN.

Pharmacogenetic approaches to hypertension therapy: design and rationale for the Genetics of Hypertension Associated Treatment (GenHAT) study

The Genetics of Hypertension Associated Treatment (GenHAT) study will determine whether variants in hypertension susceptibility genes interact with antihypertensive medication to modify coronary heart disease (CHD) risk in hypertensives. GenHAT is an ancillary study of the Antihypertensive and Lipid Lowering Treatment to Prevent Heart Attack Trial, ALLHAT, a double-blind, randomized trial of 42 418 hypertensives, 55 years of age or older, with systolic or diastolic hypertension and one or more risk factors for cardiovascular disease. About 50% are non-white, and about half are female. ALLHAT completes follow-up in March 2002. GenHAT is typing variants in hypertension genes; completion of genotyping is scheduled for 2003. Analysis of gene-treatment interactions in relation to outcomes include CHD, stroke, heart failure, and blood pressure lowering. To our knowledge, GenHAT is the largest pharmacogenetic study ever conducted. An added strength is its ability to link gene-treatment interactions with important clinical outcomes across diverse ethnic and gender groups.

Pharmacogenomics of angiotensin converting enzyme inhibitors in renal disease--pathophysiological considerations

Angiotensin converting enzyme (ACE) inhibitors preserve native kidney function in patients with renal disease better than other antihypertensive drugs, most likely because they more effectively reduce proteinuria. The plasma concentration of the ACE inhibitors target is, at least in part, under genetic control. A polymorphism of the ACE gene based on the presence or absence of a 287 base pair element in intron 16 accounts for 47% of the total phenotypic variance in the plasma ACE levels of healthy individuals. Unfortunately, pharmacogenetic studies performed so far do not provide a clear answer as to whether the efficacy of the reduction of proteinuria by ACE inhibitors is influenced by the ACE genotype - probably because these studies were not primarily designed to answer this question. This paper will try to outline some aspects that should be considered before an appropriate study on this topic is initiated.

ACE genotype and ACE inhibitor response in kidney disease: a perspective

Angiotensin-converting enzyme (ACE) inhibitors have been shown to reduce blood pressure and slow the progression of renal diseases. However, a substantial interindividual variability in treatment response also has been noted. The activity of ACE is partially dependent on the presence or absence of a 287-bp element in intron 16, and this insertion/deletion (I/D) polymorphism accounts for 47% of the total phenotypic variance in plasma ACE; DD subjects have the highest; ID subjects, intermediate; and II individuals, the lowest concentrations. Data suggest that genotype also determines tissue enzyme activity, and, at least under certain conditions, ACE activity is a rate-limiting step for angiotensin II formation. It therefore has been speculated that the ACE polymorphism also might affect therapeutic effects of ACE inhibitors. Unfortunately, clinical studies performed to date do not allow us to draw definite conclusions. Nonetheless, the rapidly evolving area of pharmacogenomics soon will also affect therapeutic decisions in the field of nephrology and hypertension.

Renoprotective effects of losartan in diabetic nephropathy: interaction with ACE insertion/deletion genotype?

BACKGROUND

The beneficial short- and long-term renoprotective effects of angiotensin I-converting enzyme (ACE) inhibition are lower in albuminuric diabetic patients homozygous for the deletion compared to the insertion polymorphism of the ACE gene. In an attempt to overcome this interaction, we evaluated the short-term renoprotective effect in diabetic nephropathy of the angiotensin II receptor antagonist losartan in patients homozygous for the insertion or the deletion allele.

METHODS

Fifty-four hypertensive type 1 diabetic patients with diabetic nephropathy homozygous for the insertion (I; N = 26) or the deletion (D; N = 28) allele of the ACE/ID polymorphism were included. After four weeks of washout, the patients received losartan 50 mg daily followed by 100 mg in two treatment periods each lasting two months. Patients and investigators were blinded to ACE genotypes. At baseline and in the end of the treatment periods, 24-hour blood pressure, albuminuria and glomerular filtration rate values were determined.

RESULTS

At baseline, blood pressure, albuminuria and glomerular filtration rate (GFR) values were similar in the two genotype groups [II vs. DD, 1134 (238 to 5302) vs. 1451 (227 to 8129) mg/24 h, median (range); 156/82 (17/9) vs. 153/80 (17/11) mm Hg, mean (SD); and 86 (22) vs. 88 (24) mL/min/1.73 m2, respectively]. Both doses of losartan significantly lowered blood pressure, albuminuria, and GFR (P < 0.05 vs. baseline). Losartan 100 mg was more effective than 50 mg in reducing albuminuria, 51% (95% CI; 40 to 61) versus 33% (23 to 42), respectively (P < 0.01). No differences in the impact of losartan between the II and DD groups were observed: Losartan 100 mg lowered systolic/diastolic blood pressure by 12/6 and 10/4 mm Hg, whereas albuminuria decreased by 55% (35 to 68) and 46% (28 to 61), in the II and DD groups, respectively (P = NS).

CONCLUSION

Our data suggest that losartan offers similar short-term renoprotective and blood pressure lowering effects in albuminuric hypertensive type 1 diabetic patients with the ACE II and DD genotypes. However, the long-term renoprotective effects remain to be evaluated.

Quinapril prevents restenosis after coronary stenting in patients with angiotensin-converting enzyme D allele

Restenosis after coronary artery stent implantation is attributed chiefly to intimal hyperplasia, which is prevented experimentally by angiotensin-converting enzyme (ACE) inhibitors. Therefore, the present study investigated whether the effect of quinapril, a tissue-specific ACE inhibitor, on the prevention of coronary restenosis differs according to ACE polymorphism. One hundred consecutive patients with successful stent implantation were randomly assigned to quinapril and control groups. Both follow-up angiography and ACE polymorphism analysis were obtained from 92 patients (control, 46; quinapril treatment, 46). The prevalence of risk factors did not differ statistically according to quinapril treatment or ACE genotypes. There was no statistically significant difference in the occurrence of restenosis 6 months after stenting between the groups. Quantitative coronary angiography revealed that quinapril treatment resulted in significantly higher minimal lumen diameter and significantly lower percent diameter stenosis (22.9 +/- 22.6 vs 37.1 +/- 19.7% in the control group, p < 0.05) in patients with the D allele although there was no difference in those with the II genotype. In addition, intravascular ultrasound revealed that quinapril treatment significantly prevented the loss of minimal lumen cross-sectional area and the increase in percent area stenosis (34.5 +/- 14.0 vs 53.3 +/- 16.4% in the control group, p < 0.05) in patients with the D allele compared to those with the II genotype. These results suggest that the administration of ACE inhibitors for the attenuation of lumen loss after coronary stent implantation is best for subjects with the D allele of the ACE genotype.

Renoprotective therapy in patients with nondiabetic nephropathies

End-stage renal failure (ESRF) represents a major health problem. Early diagnosis and effective measures to slow or to stop renal damage are essential goals for nephrologists to prevent or delay progression to ESRF. Identifying mechanisms of progressive parenchymal injury is instrumental in developing renoprotective strategies. Protein traffic through the glomerular barrier is an important determinant of progression in chronic nephropathies and proteinuria is the best predictor of renal outcome. At the moment, ACE inhibition is the most effective treatment in patients with chronic nondiabetic proteinuric nephropathies, reducing protein traffic, urinary protein excretion rate and progression to ESRF more effectively than conventional treatment. Low sodium diet and/or diuretic treatment may help to increase the antiproteinuric effect of ACE inhibitors by maximally activating the renin-angiotensin system. Intensified blood pressure control, whatever treatment is employed, also enhances the antiproteinuric response to ACE inhibitors. However, since this is not always sufficient to normalise urinary proteins and fully prevent renal damage, additional treatments may be needed in patients poorly or not responding to ACE inhibitors. These may include angiotensin II receptor antagonists, non-dihydropyridine calcium antagonists and perhaps low doses of nonsteroidal anti-inflammatory drugs. Preliminary data on multidrug treatments including these additional antiproteinuric agents are encouraging, but additional studies in larger patient numbers are needed to better define the risk/benefit profile of this innovative approach.

Loss of renal function following bone marrow transplantation: an analysis of angiotensin converting enzyme D/I polymorphism and other clinical risk factors

Chronic renal failure is an acknowledged late complication of BMT. It is related to the intensive chemotherapy, radiation and supporting medications. Polymorphism in the angiotensin converting enzyme (ACE) gene is associated with progression of nephropathy caused by diabetes and IgA nephropathy. We sought to determine whether ACE genotype and other clinical factors were associated with loss of renal function after BMT. We determined the genotype of 106 adult allogeneic BMT recipients, who received a similar preparative regimen, survived 1 year, and had assessment of renal function up to 3 years after BMT. We found that the distribution of genotypes was similar to the general population; 29%, 51%, and 20% for the DD, DI, and II genotypes, respectively. There was no statistical difference in patient survival between the three groups. Among all patients, the average creatinine clearance declined from 124 (95% CI 117, 131) to 89 (95% CI 78, 100) ml/min over the 36 months after BMT. Decline in renal function over time was less for patients with the DD compared to the II genotype (P = 0.040). Renal function in patients with the DD genotype was also better than those with the DI genotype, but this was of borderline statistical significance (P = 0.055). Renal shielding reduced decline in renal function compared to no shielding (P = 0.026). We conclude that the ACE genotype does not seem to influence survival, but the DD genotype may be protective against renal injury after BMT. Furthermore, we confirm that renal shielding during TBI reduces the renal injury after BMT.

Renin-angiotensin system gene polymorphisms: potential mechanisms for their association with cardiovascular diseases

Since the first description of the angiotensin-converting enzyme insertion/deletion polymorphism more than a decade ago, many hundreds of investigations have reported associations between this polymorphism and cardiovascular diseases. Subsequently, similar studies were performed in relationship with several other renin-angiotensin system gene polymorphisms, most notably the angiotensinogen M235T polymorphism and the angiotensin AT(1) receptor A1166C polymorphism. Surprisingly however, especially in view of the many contradictory results that have been obtained, very little attention has been paid to the mechanism(s) that may link these genetic variants and respective diseases. Here, we review the limited evidence that is currently available on the functional consequences (including compensatory mechanisms) of the above three renin-angiotensin system gene polymorphisms, in order to provide an explanation for the reported associations (or lack thereof) between these polymorphisms and cardiovascular diseases.

Angiotensin-converting enzyme gene polymorphisms in renal disease: clinically relevant?

The most recent studies of the effect of polymorphisms of the angiotensin-converting enzyme gene on the pathogenesis of renal diseases and the response to treatment with angiotensin-converting enzyme inhibitors continue to produce conflicting results. Large prospective studies are required before angiotensin-converting enzyme genotyping will provide information that will assist in the assessment of prognosis and response to angiotensin-converting enzyme inhibitor treatment in individual patients. Until such studies are performed, all patients with chronic renal disease, regardless of angiotensin-converting enzyme genotype, should be considered candidates for angiotensin-converting enzyme inhibitor therapy.

ACE DD genotype is more susceptible than ACE II and ID genotypes to the antiproteinuric effect of ACE inhibitors in patients with proteinuric non-insulin-dependent diabetes mellitus

BACKGROUND

ACE polymorphism, especially genotype DD or D allele, may be involved in the progression of diabetic nephropathy. It may also have different effects on the reduction of proteinuria by ACE inhibitors in patients with proteinuria. We investigated the relationship between ACE gene polymorphism and antiproteinuric effect of ACE inhibitors (Benazepril 10 mg/day or Perindopril 4 mg/day) in 83 NIDDM patients with overt proteinuria (urinary protein excretion over 500 mg/day).

METHODS

We recruited NIDDM patients with overt proteinuria from our renal clinic. Before entry, previously used ACE inhibitors were withdrawn for at least 2 weeks and baseline proteinuria and albuminuria were measured. Patients were classified into three groups in accordance with ACE genotypes (17 DD; 33 ID; 33 II) and prospectively followed up for 3 months. Various clinical parameters including age, DM duration, body mass index (BMI), 24-h urine sodium, protein and albumin, BUN, serum creatinine, creatinine clearance (Ccr), mean arterial pressure (MAP), and HbA(1c) were measured in the pre- and post-treatment periods. ACE genotypes were determined by polymerase chain reaction.

RESULTS

There were no significant differences in the clinical parameters such as age, DM duration, BMI, BUN, serum creatinine, Ccr, MAP, HbA(1c), and daily urinary excretion of sodium, protein and albumin among three groups (P>0.05). After the 3-month treatment period using ACE inhibitors, there were no significant differences in the reduction of MAP and Ccr among the three groups (P>0.05). However, the percentage reductions in urinary excretion of protein and albumin for DD genotype were significantly higher than in ID and II genotypes (50.9+/-19.2% vs 19.2+/-16.0%, 20.2+/-20.4%; 52.6+/-23.6% vs. 13.5+/-51.8%, 24.8+/-23.9%, P<0.05). There were no statistically significant correlations between the levels of baseline proteinuria and albuminuria and the magnitudes of the reduction of proteinuria and albuminuria under ACE inhibition (P>0.05).

CONCLUSIONS

Our results suggest that the ACE gene polymorphism might have a role in determining the responsiveness to the antiproteinuric effect of ACE inhibition in proteinuric NIDDM patients.

Angiotensin-converting enzyme gene I/D polymorphism in malignant hypertension

BACKGROUND

The mechanism of the rapid transition of a stable benign hypertensive disease to a severe and devastating malignant hypertension is not fully understood. However, the renin angiotensin system, which is highly activated in malignant hypertension, is established as an important pathogenetic factor in different cardiovascular and renal diseases. Over the last decade, a polymorphism in genes regulating this system has been found. This includes the 287 bp sequence deletion (D)/insertion (I) polymorphism in the angiotensin-converting enzyme (ACE) gene and the methionine (M) to threonine (T) point mutation polymorphism in the angiotensinogen (AGT) gene. These gene polymorphisms have been associated with various cardiovascular and renal diseases and the aim of this study was to investigate whether they were linked to malignant hypertension.

METHODS

Forty-two patients with malignant hypertension (mean age 55 years), 42 patients with non-malignant hypertension (mean age 57 years) and 85 normotensive control subjects (mean age 42 years) were investigated with respect to ACE I/D and AGT M/T genotypes. DNA was prepared by standard methods from isolated white blood cells and analysed by the PCR technique. The PCR reaction used in the detection of the ACE I/D polymorphism was optimized for an equal amplification of the I and D alleles.

RESULTS

The frequency of the DD genotype was significantly increased in patients with malignant hypertension (43%) compared with patients with non-malignant hypertension (14%) and normotensive control subjects (18%) (p <0.01) for both. The frequency distribution of AGT M/T genotype did not differ between patients with malignant and non-malignant hypertension.

CONCLUSION

The DD genotype of the ACE gene occurred more than twice as often in malignant hypertension than in non-malignant hypertension and indicates that ACE gene polymorphism is a significant risk factor for initiation of malignant hypertension.

Regression of left ventricular hypertrophy by lisinopril after renal transplantation: role of ACE gene polymorphism

BACKGROUND

Cardiac complications are the main cause of death in renal transplantation (RT), and left ventricular hypertrophy (LVH) may play an important role in these patients. The unfavorable genotype of the angiotensin-converting enzyme (ACE) gene has been associated with cardiovascular disease, including LVH. ACE inhibitors (ACEIs) reduce LVH, but little is known about the effects of ACEIs on LVH in RT patients with different insertion/deletion (I/D) genotypes of the ACE gene.

METHODS

We prospectively studied 57 stable nondiabetic RT patients with hypertension and echocardiographic LVH as well as a functional graft for 69.5 +/- 5.6 months. Patients randomly received either lisinopril 10 mg/day (group A, N = 29; 5 were excluded due to reversible acute renal failure) or placebo (group B, N = 28) for 12 months. Echocardiography (M-mode, 2-B, and color flow Doppler) was performed at baseline and 6 and 12 months later by the same examiner without previous knowledge of the genetic typing. The ACE genotype (I or D alleles) was ascertained by polymerase chain reaction (PCR; group A, DD = 10 and ID/II = 14; group B, DD = 15 and ID/II = 13).

RESULTS

All patients maintained a good renal function (serum creatinine <2.5 mg/dL) during the follow-up and both groups received a similar proportion of antihypertensive drugs (beta-blockers 83 vs. 79%; Ca antagonists 66 vs. 68%; alpha1-adrenoreceptor antagonists 50 vs. 67%) during the study. As expected, mean arterial blood pressure and hemoglobin levels showed a higher percentage reduction in group A versus group B (-4 +/- 2.8 vs. 2.1 +/- 2.6%, P = 0.07, and -11.5 +/- 1.5 vs. -0.5 +/- 2.3%, P < 0.01, respectively). Group A patients showed a significantly higher decrement in LV mass index (LVMI) than group B at the end of follow-up, after adjusting for age, baseline LVMI, time after grafting and changes in systolic blood pressure, renal function, and hemoglobin levels (group A, -9.5 +/- 3.5% vs. group B, 3 +/- 3.2%, P < 0.05). As a result, 46% of group A and only 7% of group B patients showed a reduction of LVMI >/=15% (P < 0.01). The beneficial effect of lisinopril on LVMI reduction was more evident in DD patients (placebo DD, 8.4 +/- 4.1% vs. lisinopril DD, -7.2 +/- 5.3, P < 0.05), and a trend was observed in patients with other genotypes (placebo ID/II, 2.8 +/- 5.4% vs. lisinopril ID/II, -11.4 +/- 5%, P = 0.33).

CONCLUSIONS

Lisinopril decreases LVM in renal transplant patients with hypertension and LVH, and the ACE gene polymorphism may predict the beneficial effect of this therapy. This finding may be important in targeting prophylactic interventions in this population.

Angiotensin I-converting enzyme gene polymorphism in non-diabetic renal disease

BACKGROUND

The insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene determines the concentration of ACE in serum and local tissues. The role of this polymorphism in progressive chronic renal disease is still not fully clear.

METHODS

We analysed the impact of the D/D polymorphism on the rate of decline in renal function in patients with non-diabetic, chronic progressive renal insufficiency. Seventy non-diabetic patients, aged 21-69 years at baseline, with moderately advanced renal insufficiency due to primary chronic renal disease were followed for an average of 3 years with repeated measurements of their glomerular filtration rate (GFR). Their mean GFR at baseline was 41 ml/min/1.73 m(2) body surface area (BSA). The polymerase chain reaction (PCR) amplification method was used to detect the I/D polymorphism of the ACE gene. GFR was measured as the clearance of (51)Cr-EDTA and the individual rate of progression was calculated using linear regression.

RESULTS

The distributions of the genotypes were: D/D 30%, I/D 49%, and I/I 21%. The rates of progression in the three ACE genotype groups were an annual decline in renal function of -4.2 (SD 4.6) ml/minx1.73 m(2) BSA in the D/D group, -2.7 (SD 3. 4) in the I/D group and -1.7 (SD 3.4) in the I/I group (ANOVA P=0. 12). In patients with proteinuria below 3.5 g/24 h, the D/D group had a significantly higher rate of progression than patients with the I allele. The same was found in a separate analysis when only patients with normal apoliprotein B (below 155 mg/dl) levels were analysed. Furthermore, the D/D genotype was a significant predictor of a more rapid decline in renal function in male, but not female, patients.

CONCLUSION

The results in this study in non-diabetic patients with chronic renal disease indicate that the presence of the D allele in the ACE genotype may be of particular importance as a predictor of a high rate of progression in male patients who otherwise do not have a major burden of documented and important prognostic factors for progressive renal insufficiency.

ACE gene polymorphism and renal responsiveness to ACE inhibitors in IgA nephropathy patients

We examined the renal responsiveness to ACE inhibitor in IgA nephropathy (IgAN) patients according to the grouping of ACE gene polymorphism. Sixty one patients diagnosed as IgAN by renal biopsy and prescribed with ACE inhibitors were enrolled. Genomic DNA was extracted from whole blood and PCR was performed. The I/D polymorphism was determined by the presence of the 287 bp fragment in intron 16 of chromosome 17. During the follow-up period (mean; 44.6 months, median: 44.5 months, 5 to 113 months), the blood pressure of 61 patients was controlled below 130/80 mmHg. The renal responsiveness was determined by the degree of changes of proteinuria at 12 months after initiation of ACE inhibitors and by the slope of reciprocal variation of the serum creatinine against follow-up duration ¿(1/Cr2-1/Cr1)/durations¿. The distribution of the II, ID and DD genotype among 61 patients was 21, 16 and 24 patients, respectively. There were no differences among three genotypes in age, sex, the number of patients with initial blood pressure over 140/90 mmHg, initial serum creatinine level, the number of patients with initial azotemia (> 1.4 mg/dL) and with initial 24-hr proteinuria amount over 2.0 g. Significant anti-proteinuric effect of ACE inhibitor was found in IgAN (p = 0.001), but no significant difference was found among genotypes. Significant difference (p = 0.011) was noticed between II type and DD type in the slope of reciprocal variation of the serum creatinine against follow-up duration. In conclusion, efficacy of ACE inhibitors on renal function preservation in IgAN was more pronounced in DD genotype than II genotype.

ACE genotype and ACE inhibitors induced renoprotection in chronic proteinuric nephropathies1

ACE genotype and ACE induced renoprotection in chronic proteinuric nephropathies.

BACKGROUND

Whether angiotensin-converting enzyme (ACE) gene polymorphism affects disease progression and response to ACE inhibitor therapy in nondiabetic proteinuric nephropathies is not clearly established.

METHODS

The relationship between insertion/deletion (I/D) genotypes and proteinuria, rate of glomerular filtration rate decline (DeltaGFR)-centrally evaluated by repeated measures of iohexol plasma clearance-and incidence of end-stage renal disease (ESRD) was prospectively evaluated in 212 patients with nondiabetic proteinuric chronic nephropathies enrolled in the Ramipril Efficacy in Nephropathy (REIN) trial, where patients were randomly assigned to ramipril or conventional treatment.

RESULTS

The DeltaGFR +/- SEM (-0.38 +/- 0.09 vs. -0.50 +/- 0.08 vs. -0.36 +/- 0.06 mL/min/1.73 m2 per month) and incidence of ESRD (19 vs. 22 vs. 25%) in the three subgroups with the II, ID, and DD genotypes, respectively, were comparable. Of note, DeltaGFR (-0.28 +/- 0.07 vs. -0.43 +/- 0.09 mL/min/1.73 m2 per month) and incidence of ESRD [14% vs. 36%, P = 0.04, RR (95% CI), 2.62 (1.02 to 6.71)] were lower in ramipril than in conventionally treated patients in the DD genotype, but not in the II and ID genotype. Either at univariate (P = 0.04) or at multivariate (P = 0.01) analysis, ramipril significantly predicted a lower incidence of events in DD, but not in II and ID patients. At three months, ramipril decreased proteinuria more effectively in DD (-38.2%) than in the II (-26.7%) or ID (-19.2%) genotype. In DD (but not in II or ID) ramipril-treated patients, a short-term reduction in proteinuria correlated with DeltaGFR over the entire follow-up period (P = 0.02, r = -0.41).

CONCLUSIONS

In nondiabetic proteinuric nephropathies, the ACE I/D polymorphism does not predict disease progression, but is a strong predictor of ACE inhibition-associated renoprotection in that proteinuria, DeltaGFR, and progression to ESRD are effectively reduced in patients with the DD, but not in those with the II or ID genotype.

Pharmacogenetic analysis of the effect of angiotensin-converting enzyme inhibitor on restenosis after percutaneous transluminal coronary angioplasty

Angiotensin-converting enzyme (ACE) inhibitors are reported to prevent neointimal formation after balloon injury in animal models, but in most prospective studies in humans, ACE inhibitors failed to prevent restenosis after percutaneous transluminal coronary angioplasty (PTCA). The ACE genotype assigned by an insertion/deletion (I/D) polymorphism is known to affect the potency of ACE inhibitors in several renal diseases. The authors attempted to clarify whether the effect of ACE inhibitors on restenosis might be modified by the ACE genotype. A total of 126 patients was randomly and prospectively assigned to the control group and the imidapril group. In the imidapril group, patients received 5 mg imidapril daily, starting 1 day before PTCA and continuing for 3 to 6 months. Forty-six control (65 vessels) and 32 imidapril patients (43 vessels) completed the study. The minimal lumen diameter before and after the procedure did not differ significantly among the groups with the three genotypes (II, ID, and DD) in both the control and imidapril groups. Late luminal loss during the follow-up period was not related to the ACE genotype in the control group but was significantly related in the imidapril group (II, 0.63+/- 0.19 mm; ID + DD, 1.12+/-0.14 mm, p<0.05). Furthermore, in the II genotype, imidapril significantly reduced late loss and restenosis rate as defined by most of the frequently used definitions. In conclusion the ACE I/D polymorphism may influence the effect of ACE inhibitors in preventing restenosis after PTCA.

Influence of the ACE gene polymorphism in the progression of renal failure in autosomal dominant polycystic kidney disease

The recent description of a polymorphism in the gene for angiotensin-converting enzyme (ACE), with the D allele associated with greater plasma levels of ACE, allows us to perform studies of the relationship between this polymorphism and chronic renal diseases in which the renin-angiotensin system could be implicated. We examined 155 patients with autosomal dominant polycystic kidney disease (ADPKD) with linkage to the PKD1 locus. The ACE insertion/deletion (I/D) polymorphism was amplified with the previously published flanking primers, and the polymerase chain reaction product was separated, sized on a 2% agarose gel, and visualized by ultraviolet transillumination. The ACE genotype distributions were 11.6%, 63.8%, and 24.5% for II, ID, and DD, respectively. There were no significant differences among the three genotypes with respect to mean age, sex distribution, and prevalence of hypertension. The ACE genotype distribution in patients with end-stage renal failure at the time of data compilation was similar to that of the entire study population. In the subgroup of patients who received renal replacement therapy before the age of 50 years, we found a significant association between DD genotype and onset of end-stage renal disease (ESRD) before the age of 50 years compared with II and ID (P = 0.017). We calculated the estimated median renal survival time as 51 years for the II genotype, 53 years for the ID genotype, and 48 years for the DD genotype. There were statistically significant differences between DD and ID patients (P = 0.025). In conclusion, we found DD genotype implies a worse renal prognosis based on both the significantly lower median renal survival time and significantly greater percentage of patients who reach ESRD before the age of 50 years, without implying a greater prevalence of hypertension.

Angiotensin converting enzyme gene polymorphism and ACE inhibition in diabetic nephropathy

The antiproteinuric effect of angiotensin converting enzyme (ACE) inhibition in insulin-dependent diabetes mellitus (IDDM) patients with diabetic nephropathy varies considerably. Therefore, we tested the potential role of an insertion (I)/deletion (D) polymorphism of the ACE gene on this early antiproteinuric responsiveness in an observational follow-up study. Sixty (II, N = 13; ID, N = 26 and DD, N = 21) young hypertensive IDDM patients suffering from diabetic nephropathy were investigated during three months before and for the initial six month period during ACE inhibition [captopril 44 (SD 22) mg/24 hr, no differences in drug dose between groups]. Blood pressure (MABP) and albuminuria (ELISA) were measured three (1 to 6) times before and three (1 to 13) times during ACE inhibition. At baseline the groups (II/ID/DD) had comparable (1) mean arterial blood pressure (MABP mm Hg) of 113 +/- 10/108 +/- 9/114 +/- 8, (2) albuminuria (geometric mean with 95% CI) 1394 (747 to 2608)/1176 (844 to 1797) and 1261 (827 to 2017) mg/24 hr, and (3) serum creatinine (geometric mean with 95% CI), 80 (68 to 93)/85 (76 to 97)/103 (85 to 119) mumol/liter, respectively. Angiotensin converting enzyme inhibition induced a significant reduction in MABP, albuminuria and kidney function in all three groups (II/ID/DD; P < 0.05): (1) MABP (mean +/- SD) 12 +/- 7/5 +/- 7/8 +/- 9 mm Hg (ANOVA, P = 0.02); (2) albuminuria [mean (95% CI)] 61 (34 to 77)/22 (3 to 37)/31 (13 to 46) %, (ANOVA, P < 0.01); and (3) increasing serum creatinine [mean (95% CI)] 8 (4 to 12)/9 (3 to 16)/8 (0 to 16) % (ANOVA, NS), respectively. Adjusting for differences in reduction in MABP did not change the association between decrease in albuminuria and ACE/ID genotypes (P < 0.01). A multiple linear regression analysis revealed that the ACE/ID polymorphism, albuminuria and MABP at baseline independently influenced the decline in albuminuria after initiation of ACE inhibition (R2 = 0.21, P < 0.01). A significant association between changes in MABP and albuminuria was demonstrated (R2 = 0.16, P < 0.01). Our data show that hypertensive albuminuric IDDM patients with the II genotype are particularly susceptible to commonly advocated renoprotective treatment.

Association of the angiotensin I converting enzyme gene deletion polymorphism with early onset of ESRF in PKD1 adult polycystic kidney disease

To determine the effect of the ACE gene insertion/deletion (I/D) polymorphism, angiotensinogen gene M235T polymorphism and the angiotensin 1 receptor gene A1166C polymorphism on the age of onset of end-stage renal failure (ESRF) in PKD1 adult autosomal-dominant polycystic kidney disease (ADPKD), 189 individuals from 46 families with PKD1 were genotyped for each polymorphism. Of the 189 patients 52 (28%) reached ESRF at an average age of 48 +/- 1 year. In patients genotyped for the ACE gene insertion/deletion polymorphism the frequencies of the DD, ID and II genotypes were similar to those expected from Hardy Weinberg equilibrium. In patients with ESRF there was an excess of patients homozygous for the deletion allele (DD: 48% chi2 = 9.97 (1df) P = 0.002). Cumulative renal survival was significantly reduced among those with DD genotype compared to ID and II genotypes. The estimated mean renal survival (95% confidence intervals) were: DD, 52 years [48, 57]; II, 59 years [54, 63]; ID, 64 years [56, 72]; chi2 = 6.13 (1df) P = 0.013, DD versus ID/II. The mean age of renal failure was significantly younger in the DD genotype compared to ID and II genotypes (DD, ID, and II: 44 +/- 2, 49 +/- 2 and 54 +/- 3 years, respectively; P < 0.05 DD vs. ID, P < 0.05 DD vs. II). Ten of the eleven patients who reached ESRF before the age of 40 were homozygous for the deletion allele. The relative risk for ESRF below the age 40 for DD genotype was 17. For all ages there was an overall increased risk of 1.4 for ESRF with the DD genotype. There was no interaction between age of onset of ESRF and either the angiotensinogen M235T allele or angiotensin 1 receptor A1166C polymorphism. This study strongly suggests that PKD 1 patients homozygous for the deletion allele of the ACE gene are at increased risk of developing ESRF at a early age.