Is PstI polymorphism of the angiotensin I converting enzyme gene associated with nephropathy development in non-insulin-dependent diabetes mellitus (preliminary study)

Nephropathy is a frequent complication of long term diabetes. Diabetic nephropathy is the major determinant of premature morbidity and mortality both in insulin-dependent (IDDM) and in non-insulin dependent-diabetes mellitus (NIDDM). There is good evidence that genetic predisposition plays a major role in development of diabetic nephropathy. This hypothesis is based on the observation that diabetic nephropathy clusters within families, both in IDDM and NIDDM. Components of the renin-angiotensin system (RAS) are plausible candidate genes to examine for a association with microalbuminuria and diabetic nephropathy. In this study we compared the distribution of PstI melting polymorphism at the ACE locus among NIDDM patients with diabetic nephropathy and in patients who, despite long duration of NIDDM, remain without this complication. The 220 NIDDM patients for whom DNA was available were classified into two groups according to their renal status: normoalbuminuric control subjects (n = 80) who are NIDDM patients with an A/C ratio < 2.5 and nephropathy cases (n = 140) who are NIDDM patients with A/C ratio > 2.5. Albumin excretion rate was assayed by radioimmunoassay. HbA1c was assayed using HPLC methods, creatinine--using Jaffe methods and DNA analysis using PCR reaction, and then after the amplification product was digested with PstI enzyme. The study revealed that PstI sequence differences ("+/= and -") in the ACE gene do not contribute to genetic susceptibility to diabetic nephropathy in NIDDM.     

Angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism, and diabetic retinopathy in subjects with IDDM and NIDDM

Angiotensin 1 converting enzyme (ACE) catalyses the step which generates angiotensin II, and also inactivates bradykinin, peptides which play a key role in modulating vascular tone. Plasma ACE levels are under genetic control and up to 50% of the variation is due to an insertion/deletion (I/D) polymorphism of ACE gene with highest levels found in DD homozygotes. Studies have shown an association of diabetic nephropathy and ischaemic heart disease with angiotensin converting enzyme gene polymorphism in subjects with diabetes. We examined the association between diabetic retinopathy and ACE gene insertion/deletion polymorphism in 363 subjects with NIDDM (aged 68.3 +/- 10.7 years; 201 male, 162 female), 186 subjects with IDDM (aged 42.4 +/- 15.0 years; 100 male, 86 female) and 98 controls. These subjects were characterized for ACE I/D polymorphism employing standard primers. Diabetic retinopathy was diagnosed by ophthalmoscopy through dilated pupils by an ophthalmologist and classified as non-proliferative or proliferative retinopathy. As expected, diabetic retinopathy was strongly associated with duration of diabetes (p < 0.001) in both IDDM and NIDDM. Any retinopathy was present in 51% subjects with IDDM and 49% of subjects with NIDDM, while 22% of IDDM subjects and 5% of subjects with NIDDM had proliferative retinopathy. The frequency of I allele was 0.477 vs 0.482 vs 0.510 and D allele was 0.523 vs 0.518 vs 0.490, among subjects with IDDM, NIDDM and controls, respectively. The frequency of ACE I/D genotype was similar in subjects with IDDM, NIDDM, and controls (chi 2 = 0.46, df = 4, p = ns). Presence or absence of retinopathy was not significantly associated with ACE genotype in subjects with IDDM (chi 2 = 3.42, df = 2, p = ns) or NIDDM (chi 2 = 0.51, df = 2, p = ns). Among subjects with retinopathy, there was no significant association between ACE genotype and type of retinopathy. Controlled for duration of diabetes, the frequency of I/D genotype was not significantly different in 271 subjects with retinopathy (IDDM and NIDDM combined) when compared with 86 subjects without retinopathy at 15 years or more after diagnosis of diabetes (chi 2 = 1.29, df = 2, p = ns). These findings indicate that I/D polymorphism of ACE gene is not a useful marker and is unlikely to play a major role in determining genetic susceptibility to diabetic retinopathy or the severity of diabetic retinopathy.     

Electroneutral Na-coupled cotransporter expression in the kidney during variations of NaCl and water metabolism

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.     

Benefits and cost of antihypertensive treatment in incipient and overt diabetic nephropathy

PREVALENCE: The prevalence of abnormally elevated urinary albumin excretion rate (> 30 mg/24 h) is approximately 40% in insulin-dependent and in non-insulin-dependent diabetic patients. Diabetes has become the leading cause of end-stage renal failure in Europe, USA and Japan. Approximately 90% of the direct and indirect costs of caring for diabetic patients are spent on the complications of diabetes. RISK FACTORS: Identification of patients at high risk of developing diabetic nephropathy is possible by screening for microalbuminuria (30-300 mg/24 h). Additional risk factors/ markers for development of nephropathy are male sex, genetic predisposition, ethnic conditions, early onset of diabetes, poor metabolic control, hyperfiltration, elevated prorenin and smoking. Elevated urinary albumin excretion rate indicates a substantially increased cardiovascular morbidity and mortality risk in diabetic patients. PREVENTION OF NEPHROPATHY: Randomized controlled trials in normotensive insulin-dependent and in non-insulin-dependent diabetic patients with persistent microalbuminuria indicate that angiotensin converting enzyme (ACE) inhibitors diminish urinary albumin excretion rate, and postpone and may even prevent progression to clinical overt nephropathy. These findings indicate that screening and intervention programs could probably save lives and lead to considerable economic savings. TREATMENT OF NEPHROPATHY: Systemic blood pressure elevation to a hypertensive level is an early and frequent phenomenon in diabetic nephropathy. Furthermore, nocturnal blood pressure elevation (non-dippers) occurs more frequently in patients with nephropathy. Systemic blood pressure elevation, hyperglycaemia, albuminuria and the D polymorphism in the ACE gene accelerate the progression of diabetic nephropathy. Studies of the impact of other potential progression promoters (i.e. smoking, hyperlipidaemia and protein intake) have yielded conflicting results. Effective blood pressure reduction using ACE inhibitors or drugs of other classes, or both, frequently in combination with diuretics reduces albuminuria, delays the progression of nephropathy, postpones renal failure and improves survival in patients with diabetic nephropathy. Antihypertensive treatment for diabetic nephropathy extends life and saves money.     

Pain in the back

OBJECTIVE: To establish a method for sensitive, specific and rapid detection of the angiotensin converting enzyme(ACE) genotypes and to study the relationship between the ACE gene polymorphism and preeclampsia. METHODS: Sixty patients with preeclampsia and 76 normal pregnant women as controls were investigated. A pair of primers, for the intron 16 of ACE gene was designed. A sensitive and specific method for detecting the ACE polymorphism of the insertion/deletion was established. Determined by polymerase chain reaction (PCR),a 490bp(I) and 190bp(D) PCR product was identified,corresponding to the PCR amplification of the allele with or without the insertion. RESULTS: The subjects were classified, according to the presence or absence of a 287bp insertion in intron 16 of the ACE gene, as II, DD, or heterozygotes for deletion/insertion (DI). The frequency of allele gene (0.75) and the percentage of the ACE DD genotype (65%) in the preeclampsia group were significantly higher as compared with the frequency 10.308 and the percentage (10.5%) in the control group respectively. CONCLUSION: Genotype II of ACE is a marker for reduced risk for preeclampsia and DD is a risk gene.     

Role of the deletion of polymorphism of the angiotensin converting enzyme gene in the progression and therapeutic responsiveness of IgA nephropathy

Studies conducted over the last decade demonstrated variable therapeutic efficacy of angiotensin converting enzyme (ACE) inhibitor on the progression of glomerular diseases, including IgA nephropathy. In this study, among patients with biopsy-proven IgA nephropathy, 53 patients in whom creatinine clearance had been monitored over 5 yr were recruited for study. These patients were classified into two groups according to whether or not renal function had declined as determined by the slope of creatinine clearance against time: group 1 had stable renal function; group 2 had declining renal function (average: -6.7 +/- 1.3 ml/min/yr). 21 of 53 patients were treated with ACE inhibitor and followed for 48 wk. Gene polymorphism consisting of insertion (I) or deletion (D) of a 287-bp DNA fragment (presumed to be a silencer element) of the ACE gene was determined by PCR. 46 age-matched individuals without history of proteinuria were analyzed as controls. The DD genotype was significantly more frequent in group 2 (43%) than in controls (7%) or group 1 patients with stable renal function (16%). 48 wk after ACE inhibitor administration, proteinuria significantly decreased in patients with DD genotype but not in those with ID or II genotypes. The results indicate that deletion polymorphism in the ACE gene, particularly the homozygote DD, is a risk factor for progression to chronic renal failure in IgA nephropathy. Moreover, this deletion polymorphism predicts the therapeutic efficacy of ACE inhibition on proteinuria and, potentially, on progressive deterioration of renal function.     

Association between the angiotensin-converting enzyme-insertion/deletion polymorphism and diabetic nephropathy: a methodologic appraisal and systematic review

Recent studies have implicated a variant of the angiotensin-converting enzyme gene (ACE), associated with increased activity of this enzyme, in the development and progression of diabetic nephropathy. This study provides a systematic review of all cross-sectional, case-control, and cohort studies in patients with insulin-dependent (IDDM) or non-insulin-dependent (NIDDM) diabetes mellitus of any race, examining the relationship between the ACE-insertion/deletion polymorphism and nephropathy. Nineteen studies in 21 populations published between 1994 and 1997 presenting data on 5336 patients were reviewed. Two investigators independently assessed the studies on methodologic quality, performance of study, and association between the ACE-insertion/deletion polymorphism and nephropathy. Separate analyses of the relationship between genotype and allele frequencies were performed for patients with IDDM and NIDDM by race, using Peto's odds ratio. In Caucasians with IDDM, pooling was not performed due to heterogeneity of the studies, but among the homogeneous studies, no association was detected. Likewise, no association was observed in Caucasian patients with NIDDM (odds ratio [OR], 1.10; 95% confidence interval [95% CI], 0.83 to 1.45). In Asian patients with NIDDM, the risk of nephropathy was increased in the presence of the DD or ID genotype (OR, 1.88; 95% CI, 1.42 to 2.85). Although this analysis fails to confirm an association between the ACE-insertion/deletion genotype and nephropathy in Caucasians with NIDDM or IDDM, a role for this genetic marker in Asian patients cannot be ruled out. However, due to methodologic limitations of individual studies, no definite conclusions can be drawn from this analysis. Clearly, more rigorous methodology needs to be applied in future studies.     

Screening of the TAP1 gene by denaturing gradient gel electrophoresis in insulin-dependent diabetes mellitus: detection and comparison of new polymorphisms between patients and controls

New protective or disease-associated polymorphisms in the TAP1 gene were sought in insulin-dependent diabetes mellitus (IDDM) patients with the use of denaturing gradient gel electrophoresis (DGGE) screening of genomic DNA. The TAP1 gene is located in the human leukocyte antigen (HLA) class II region of the genome and encodes components of a peptide transporter essential for antigen presentation by HLA class I molecules. Fragments of TAP1 corresponding to the 5' promoter, each of the 11 exons (with portions of adjacent intronic regions) and the 3' flanking region were amplified by the polymerase chain reaction and then subjected to DGGE. DNA fragments of TAP1 yielded DGGE bands with patterns whose frequencies differed between IDDM patients and controls. Specific DGGE band patterns with fragments corresponding to the promoter, exons or introns 3, 6, 7, 8, 9 or 10 of TAP1 were detected exclusively in either patients or controls. Sequencing of TAP1 fragments encompassing exon 7 gave rise to a DGGE band pattern exclusively observed in an IDDM patient and sequencing revealed a previously unidentified polymorphisms at codon 518 (GTC-->ATC, Val-->Ile). Another unique polymorphism uncovered by DGGE revealed by sequencing a polymorphism in intron 2 in a diabetic patient. The genotypes of additional HLA class II matched patients and controls were determined with regard to five exonic and one intronic TAP1 polymorphism. A 10 base pair intronic insertion in intron 9 was exclusively identified in controls and missing from patients (P = 0.017). Further large population-based studies may reveal whether these newly identified at risk or protective TAP1 variants confer markers of statistical risk in diverse population groups.     

Therapy of diabetic nephropathy. Effects of ACE inhibition on microcirculation

The development of diabetic microangiopathies is of decisive importance for the long-term prognosis of diabetes mellitus. For example, diabetic nephropathy is one of the the most common causes of terminal kidney failure. Primary prevention of diabetic nephropathy is best achieved by establishing good metabolic control. To ensure early pharmacological intervention of incipient diabetic nephropathy, screening for microalbuminuria is recommended at least once a year. A major element in the pathogenesis of diabetic nephropathy is a disordered microcirculation characterized by abnormal hemodynamics with elevated capillary pressure and microvascular resistance. Angiotensin converting enzyme inhibitors (ACE inhibitors) effectively act on these pathophysiological events by dilation of the vasa efferentia of the glomeruli. By means of videocapillaroscopy and laser doppler imaging also distinct changes in microcirculation can be detected. Investigations with these methods provided evidence that ACE inhibitors might also be useful in the primary prevention of diabetic nephropathy. Therefore, ACE inhibitors are useful pharmaceutical agents in the treatment of diabetic nephropathy.     

Diabetic nephropathy. Its relationship to hypertension and means of pharmacological intervention

Hypertension and diabetes mellitus are common chronic conditions which frequently coexist. Diabetic nephropathy is a major cause of elevated blood pressure in patients with insulin-dependent diabetes mellitus (IDDM). Diabetic nephropathy, arterial sclerosis, obesity and association of essential hypertension can be the causes of hypertension in patients with non-insulin-dependent diabetes mellitus (NIDDM). Ambulatory blood pressure monitoring has revealed that the nocturnal fall of blood pressure is blunted in patients with diabetic nephropathy. A blunted diurnal blood pressure variation is seen in microalbuminuric diabetic patients and even in some normoalbuminuric patients. Accumulating data suggest that normalisation of blood pressure in hypertensive IDDM patients is most important to minimise the loss of kidney function. Angiotensin converting enzyme (ACE) inhibitors have been reported to be effective in postponing the development of nephropathy and in slowing its progression. Whether only ACE inhibitors have such beneficial renal effects on diabetic nephropathy is under discussion. While many studies have suggested that insulin resistance and hyperinsulinaemia are related to an elevated blood pressure in hypertensive patients, there does not seem to be enough evidence to prove that insulin per se can raise blood pressure in humans. Neither an insulin infusion within a physiological range nor sustained hyperinsulinaemia and insulin resistance (e.g. patients with insulinoma, cystic ovary syndrome) have been associated with an elevated blood pressure. Insulin resistance in some hypertensive patients may be a consequence of a decreased blood flow due to an increased peripheral resistance. Preliminary evidence suggests that low birth weight or impaired fetal growth is related to hypertension and NIDDM. Familial clustering of diabetic nephropathy suggests the contribution of genetic susceptibility and/or environmental inheritance. The frequent association of nephropathy with hypertension has led to research on the genes related to hypertension (ACE, angiotensinogen). Nevertheless, to date no reliable and clinically useful genetic marker has been found. Attempts to correct the metabolic abnormalities derived from diabetes are a new topic in the treatment of diabetic nephropathy. The effects of HMG CoA reductase inhibitors (antihypercholesterolaemic drugs), aldose reductase inhibitors (inhibitors of the polyol pathway) and glycation inhibitors (inhibitors of formation of advanced glycosylation end-products) on diabetic nephropathy have been evaluated in animal studies and in some clinical trials. Thus far, results with HMG CoA reductase and aldose reductase inhibitors have been somewhat conflicting. The potential therapeutic role of glycation inhibition in the treatment of diabetes deserves further study.     

The role of bronchial biopsy and washing in the diagnosis of allergic bronchopulmonary aspergillosis

A polymorphism in the angiotensin I-converting enzyme (ACE) gene has been associated with cerebrovascular diseases as a new potent risk factor. The purpose of this study was to investigate an association of the gene polymorphism with intracranial saccural aneurysmal patients. The study population consisted of 83 aneurysmal patients (age range 41-85 years) (the AN group) and 104 matched control subjects (age range 30-81 years) (the Control group). For detection of the ACE gene polymorphism, the standard PCR method was performed by using genomic DNA isolated from peripheral blood leukocytes. The PCR products were a 490-bp in the presence of the insertion (I) and a 190-bp fragment in the absence of the insertion (D). The ACE gene polymorphism was classified into three genotypes: I/I genotype (a 490-bp band); D/D genotype (a 190-bp band); or I/D genotype (both a 490-bp and a 190-bp band). The number of subjects with I/I, I/D, and D/D genotypes was 38, 40, and 5 in the AN group and 43, 45, and 16 in the Control group, respectively. The frequency of the D/D genotype in the AN group was significantly lower (5/83 = 0.06) than that in the Control group (16/104 = 0.15) (chi 2 = 4.06; p = 0.044). There was no significant difference between the genotype sof hypertensive patients and normotensive patients in the AN group. Thus, this present study suggests that genetic heterogeneity of the ACE gene may be correlated with the etiology of intracranial aneurysms.     

Therapeutic interventions for nephropathy in type I diabetes mellitus

Diabetic nephropathy is the single most common cause of end-stage renal disease in the United States. Recently, several major therapeutic interventions have been developed and shown to slow or halt the progression of renal failure in patients with diabetes and diabetic kidney disease. Studies have shown that in patients with insulin-dependent diabetes and proteinuria, lowering systemic blood pressure slows the rate of decline in renal function and improves patients' survival. In the recently completed trial of angiotensin converting enzyme (ACE) inhibition in diabetic nephropathy, ACE inhibitors were specifically shown to decrease dramatically the risk of doubling of serum creatinine or reaching a combined outcome of end-stage renal disease or death independent of their effect on systemic blood pressure. In studies with small numbers of patients, dietary protein restriction has also been shown to slow the rate of decline of renal function. New potential interventions currently undergoing study include treatment with aldose reductase inhibitors, treatment with inhibitors of the formation of advanced glycosylation end-products, treatment of dyslipidemia, and a variety of other less well-studied interventions.     

Renal protection and angiotensin converting enzyme inhibition in microalbuminuric type I and type II diabetic patients

BACKGROUND: Many studies have emphasized the role of antihypertensive drugs and in particular angiotension converting enzyme (ACE) inhibitors in the retardation of diabetic nephropathy. Although these studies have focused predominantly on patients with overt proteinuria, more recently a number of investigators have explored the role of ACE inhibitors in both type I and type II diabetic patients with an earlier phase of diabetic renal disease known as microalbuminuria. These agents are now being considered as renoprotective agents not only in hypertensive patients but also in those with 'normal' blood pressure. Initially, studies in type I diabetic patients showed that ACE inhibition was effective in retarding the increase in albuminuria which was observed in placebo treated groups. More recently, several multi-centre placebo controlled studies have been performed suggesting that prolonged treatment not only reduced albuminuria but also preserved renal function. The role of ACE inhibition in microalbuminuric type II diabetic patients is less well characterised although several studies have recently described beneficial effects of ACE inhibition on albuminuria and possibly on renal function. REVIEW: Although ACE inhibitors have been clearly shown to reduce urinary albumin excretion in diabetic patients, the issue as to whether they confer a specific benefit over other classes of antihypertensive agents remains controversial. Several meta-analyses have suggested that ACE inhibitors are more potent at decreasing albuminuria or proteinuria than other antihypertensive agents, for a given reduction in blood pressure. The Melbourne Diabetic Nephropathy Study Group has instituted a study which is placebo-controlled and is confined to normotensive type I and type II diabetic patients. The ACE inhibitor perindopril has been compared not only with placebo but also with the dihydropyridine calcium channel blocker, nifedipine. Preliminary analysis reveals that after 12 and 24 months of treatment, perindopril is more effective in reducing albuminuria than placebo or nifedipine. CONCLUSION: ACE inhibitors are a promising class of antihypertensive agents in diabetic patients with microalbuminuria. These drugs should be considered as first line agents in such patients, even in the absence of systemic hypertension.     

Diabetic nephropathy is associated with AGT polymorphism T235: results of a family-based study

Diabetic nephropathy is a serious and frequent complication of insulin-dependent diabetes mellitus (IDDM) that has a strong genetic component. Several case-control studies have reported conflicting results with regard to the role of angiotensinogen gene polymorphisms, specifically the M235T T allele, in the development of diabetic nephropathy. The primary limitation of the case-control approach is that bias may be introduced by unrecognized differences in the populations selected for cases and control subjects. In contrast, family-based approaches, such as the transmission/disequilibrium test, assess whether a particular variant, or allele, is transmitted preferentially from a parent having a single copy of that allele. Thus each family provides its own control, thereby eliminating spurious results caused by mismatched population samples. To take advantage of this study design for further investigation of M235T, we collected from the Joslin Diabetes Center in Boston 148 IDDM patients with diabetic nephropathy, 62 nephropathy-free patients with long-duration IDDM, and, very importantly, parents of all these individuals. We found that among males (but not females) the T allele of the M235T polymorphism was transmitted preferentially to those with nephropathy compared with IDDM patients without nephropathy (P=.05). Moreover, the T allele was transmitted preferentially to patients with the most severe manifestation of nephropathy, end-stage renal disease (P=.04). In conclusion, results obtained in our family-based study support a role of the angiotensinogen gene M235T polymorphism, and specifically the T allele, in the development of diabetic nephropathy in IDDM.     

Beta-lactamase-producing bacteria in recurrent childhood tonsillitis

Angiotensin converting enzyme is a key component of the renin angiotensin system that plays an important role in cardiovascular regulation. It seems to modulate cardiovascular growth by virtue of its role in the conversion of angiotensin I to angiotensin II and degradation of kinins. A deletion polymorphism localized in intron 16 of the human angiotensin converting enzyme gene, corresponding to a 287 bp long Alu repetitive sequence, was found to be associated with increased risk of myocardial infarction in various subgroups, including European, French and Japanese coronary patients. This angiotensin converting enzyme gene I/D polymorphism was examined by the polymerase chain reaction in a cross-sectional study of 201 healthy Indian subjects and 150 patients (angiographically proven cases of coronary artery disease) whose serum angiotensin converting enzyme levels were concomitantly measured. The D/D, I/D and I/I genotypes were found in 20.66%, 46.66% and 32.66% of the Indian coronary heart disease patients and in 23.38%, 49.75% and 26.86% of controls respectively. One of the reasons for not finding an association between the D allele and coronary artery disease in this study could be the ethnic heterogeneity and disease status heterogeneity among the patients and controls. However the phenotypic variance of serum angiotensin converting enzyme levels is strongly influenced by this polymorphism. In the Indian population, the angiotensin converting enzyme gene I/D polymorphism is not associated with risk for coronary artery disease although it is associated with plasma angiotensin converting enzyme activity. Hence the angiotensin converting enzyme gene I/D polymorphism does not seem to be a useful marker for coronary artery disease in the Indian population.     

Brain alcohol detectability increase with repeated administration in humans: a proton spectroscopy study

BACKGROUND AND PURPOSE: There is evidence that an allelic variation in the angiotensin-converting enzyme (ACE) gene may confer an increased risk of vascular disease. The roles of the ACE insertion/deletion polymorphism and circulating ACE levels are unknown in cerebrovascular disease. METHODS: We studied an insertion/deletion polymorphism within intron 16 of the ACE gene by polymerase chain reaction and plasma ACE activity in 467 cases of stroke, the pathological type of which was established by cranial CT, and 231 control subjects. ACE genotype and activity were related to stroke type and mortality at 4 weeks and 3 months. RESULTS: No difference in genotype frequency was observed between all subjects with stroke and control subjects or between control subjects and subjects with cerebral infarction or cerebral hemorrhage. Plasma ACE activity was significantly lower in stroke patients at presentation (64.1 IU/L) than in control subjects (79.6 IU/L; P<.0001). Twenty-one patients (4.5%) with cerebral infarction died within 4 weeks and 56 patients (12%) within 3 months. These patients had significantly lower plasma ACE activity than patients who survived. There was some evidence that risk of death within 4 weeks increased with the number of D alleles (P=.02). Among survivors, plasma ACE activity showed a mean increase of 6.9 IU/L (95% confidence interval, 3.0 to 10.8) between levels at presentation and at 3 months (73.6 IU/L), the latter being similar to ACE activity in control subjects. CONCLUSIONS: Low ACE activity at sroke presentation and possession of the D allele may be associated with increased risk of early death from acute cerebral infarction.     

Can we further slow down the progression to end-stage renal disease in diabetic hypertensive patients?

HYPERTENSION AND DIABETES: Hypertension occurs about twice as frequently in diabetics compared with the general population, with a prevalence of approximately 25% in young patients with insulin-dependent diabetes mellitus (IDDM) and 50% in newly diagnosed non-IDDM (NIDDM) patients. Studies strongly suggest that hypertensions is involved in the progression and perhaps the onset of diabetic nephropathy, which is a major cause of illness and premature death in diabetic patients, largely through accompanying cardiovascular disease and end-stage renal failure. TREATMENT: A large body of evidence has accumulated which emphasizes the beneficial effects of antihypertensive treatment in reducing proteinuria and preserving renal function in both IDDM and NIDDM. It appears that angiotensin converting enzyme inhibitors and certain calcium antagonists, notably the non-dihydropyridine type and second-generation dihydropyridine calcium antagonists, produce a more beneficial effect on nephropathy in terms of reducing proteinuria and slowing progression in renal failure. These drugs have displayed a nephroprotective capacity beyond their systemic blood pressure-lowering effects, and initial clinical trials with combinations of different antihypertensive drug classes have revealed additive effects in reducing albuminuria together with the lowest rate of decline in glomerular filtration rates with the lowest incidence of adverse effects. AVAILABLE STUDIES: The studies available on antihypertensive treatment in IDDM and NIDDM patients with incipient or overt diabetic nephropathy are mainly prospective. There have also been some preliminary trials with antihypertensive combinations in diabetic patients.     

High prevalence of risk factors for cardiovascular disease in parents of IDDM patients with albuminuria

Life expectancy is shorter in the subset of insulin-dependent diabetic (IDDM) patients who are susceptible to kidney disease. Familial factors may be important. In this study the prevalence of cardiovascular disease mortality and morbidity and of risk factors for cardiovascular disease was compared in the parents of 31 IDDM patients with elevated albumin excretion rate (AER > 45 microg/min; group A) with that of parents of 31 insulin-dependent diabetic patients with normoalbuminuria (AER < 20 microg/min; group B). The two diabetic patient groups were matched for age and duration of disease. Information on deceased parents was obtained from death certificates and clinical records and morbidity for cardiovascular disease was ascertained using the World Health Organization questionnaire and Minnesota coded ECG. Hyperlipidaemia was defined as serum cholesterol higher than 6 mmol/l and/or plasma triglycerides higher than 2.3 mmol/l and/or lipid lowering therapy; arterial hypertension as systolic blood pressure higher than 140 mmHg and/or diastolic blood pressure higher than 90 mmHg and/or antihypertensive treatment. The percentage of dead parents was similar in the two groups (26 vs 20% for parents of group A vs group B, respectively), but the parents of the diabetic patients with elevated AER had died at a younger age (58 +/- 10 vs 70 +/- 14 years; p < 0.05). Parents of diabetic patients with nephropathy had a more than three times greater frequency of combined mortality and morbidity for cardiovascular disease than that of the parents of diabetic patients without nephropathy (26 vs 8%; odds ratio 3.96, 95% CI 1.3 to 12.2; p < 0.02). Living parents of group A had a higher prevalence of arterial hypertension (42 vs 14% p < 0.01) and hyperlipidaemia (49 vs 26% p < 0.05) as well as higher levels of lipoprotein (a) [median (range) 27.2 (1-107) vs 15.6 (0.2-98) mg/dl; p < 0.05]. They also had reduced insulin sensitivity [insulin tolerance test: median (range) K(itt) index: 3.7 (0.7-6.2) vs 4.8 (0.7-6.7)% per min; p < 0.05]. In the families of IDDM patients with elevated AER there was a higher frequency of risk factors for cardiovascular disease as well as a predisposition to cardiovascular disease events. This may help explain, in part, the high prevalence of cardiovascular disease mortality and morbidity in those IDDM patients who develop nephropathy.     

Hyperhomocyst(e)inemia and endothelial dysfunction in IDDM

OBJECTIVE: While elevated blood levels of homocyst(e)ine represent an independent risk factor for macrovascular disease, we assessed the link between hyperhomocyst(e)inemia and diabetic microvascular diseases. RESEARCH DESIGN AND METHODS: Plasma levels of homocyst(e)ine and thrombomodulin (TM), markers of endothelial cell damage, were measured before and 3 h after oral methionine loading in 75 patients with IDDM and 40 healthy control subjects matched for sex and age. Exclusion criteria were hyperlipidemia, hypertension, smoking, or positive family history for cardiovascular disease. RESULTS: IDDM patients had higher pre- and postload plasma levels of homocyst(e)ine than did healthy control subjects (12.0 vs. 7.7 mumol/l and 27.6 vs. 16.0 mumol/l; P < 0.001). Of 75 IDDM patients, 26 had plasma homocyst(e)ine levels above the normal range (means +/- 2 SD of values obtained in the control group). These IDDM patients with hyperhomocyst(e)inemia had higher plasma TM levels (62.2 vs. 38.2 ng/ml, P < 0.001), higher albumin excretion rates (485 vs. 115 mg/l, P < 0.005), and a higher prevalence of late diabetic complications (nephropathy, 76 vs. 33%; retinopathy, 69 vs. 51%; neuropathy, 57 vs. 41%; and macroangiopathy, 57 vs. 33%) compared with IDDM patients with normal plasma homocyst(e)ine. In vitro experiments with human umbilical vein cells showed an increased release of TM into the culture supernatant only when endothelial cells were pretreated with advanced glycation end product (AGE)-albumin before L-homocystine was added. A synergistic action of homocyst(e)ine and AGEs might contribute to vascular complications in patients with diabetes. CONCLUSIONS: Hyperhomocyst(e)inemia is common in nephropathic diabetic patients and may contribute to the enhanced morbidity and mortality from cardiovascular diseases characteristically observed in IDDM patients with diabetic nephropathy.