Role of blood pressure in the progression of microalbuminuria in elderly Japanese type 2 diabetic patients: a 7-year follow-up study

Diabetic nephropathy in the elderly

Renal impairment is frequent in aged diabetic patients, notably with type 2 diabetes. It results from a multifactorial pathogeny, particularly the combined actions of hyperglycaemia, arterial hypertension and ageing. Diabetic nephropathy (DN) is associated with an increased cardiovascular mortality. DN often leads to end stage renal failure (ESRF) which causes specific problems of decision and practical organization of extra-renal epuration in diabetic and aged patients. In the absence of renal biopsy, clinical signs are often insufficient to assess the diabetic origin of a nephropathy in an elderly diabetic patient. Prevention of DN is principally based on tight glycaemic and blood pressure control. The progression of renal lesions can be retarded by strict blood pressure control, notably by blocking of the renin-angiotensin system, if well tolerated in aged patients. It is absolutely necessary to avoid the worsening of renal lesions by potentially nephrotoxic products, notably non steroidal anti-inflammatory drugs (NSAIDs) and iodinated contrast media. At the stage of renal failure, it is important to adapt the antidiabetic treatment, and in the majority of the cases, to switch to insulin when glomerular filtration rate (GFR) is below 30 ml/mn/1.73 m2.

Enalapril and losartan affect lipid peroxidation in renal transplant recipients with renin–angiotensin system polymorphisms

OBJECTIVES

In this study, the effect of enalapril (E) and/or losartan (L) on lipid peroxidation (LPO) is studied in renal transplant recipients (RTRs) with regard to polymorphisms of renin-angiotensin system (RAS).

DESIGN AND METHODS

After determination of genotypes of the angiotensin-converting enzyme (ACE I/D), angiotensinogen (AGT M235T) and angiotensin II type 1 receptor (ATR1 A1166C) by PCR, sixty-four RTRs recruited to four groups randomly: first (13 patients) and second (20 patients) groups were treated with enalapril (E(+): 10 mg/day) and losartan (L(+): 50 mg/day) alone for 2 months, respectively. After 2 weeks as washout period, E group changed to L and vice versa as a cross-over design and they were treated for another 2 months. The third group (13 patients) as positive control received enalapril+losartan (E(+)L(+): 10 mg/day+50 mg/day) for 16 weeks, and the forth group (18 patients) as negative control received no medication (E(-)L(-)). Malondialdehyde (MDA) as LPO marker was measured before and after treatment. In this study, P<0.05 was considered significant.

RESULTS

After 2 months of treatment, MDA level significantly decreased in all of the groups except the E(-)L(-). MDA level in pre- vs. post-intervention for the E(+)L(+), E(+), L(+) and E(-)L(-) groups were as follows: 5.81+/-2.13 nmol/mL vs. 1.61+/-0.80 nmol/mL (P=0.001), 5.10+/-2.05 nmol/mL vs. 1.68+/-1.01 nmol/mL (P=0.003), 5.20+/-1.61 nmol/mL vs. 1.22+/-0.27 nmol/mL (P=0.000) and 5.27+/-2.12 nmol/mL vs. 5.07+/-2.03 nmol/mL (P=0.52), respectively. Also, the same results were found in the end of 16th week. Although patients with DD genotype of ACE had higher MDA (P=0.01) levels, RAS polymorphisms could not predict the antioxidative response rate to the drugs (P>0.05).

CONCLUSIONS

E and/or L reduce MDA regardless of the RAS genotypes.

A comparison of urinary albumin excretion rate and microalbuminuria in various glucose tolerance subjects

AIMS

To investigate the difference of urinary albumin excretion rate (UAER) and microalbuminuria (MAU) in various glucose tolerance subjects, especially between isolated-impaired glucose tolerance subjects and isolated-impaired fasting glycaemia subjects.

METHODS

A total of 2934 subjects were divided into five groups with various glucose tolerances, based on a 75-g oral glucose tolerance test. Microalbuminuria was defined when urinary albumin excretion rate was between 20 and 200 microg/min.

RESULTS

(i) The UAER in the newly diagnosed Type 2 diabetes mellitus group, impaired glucose tolerance/impaired fasting glycaemia group and isolated-impaired glucose tolerance group were all higher than that in the isolated-impaired fasting glycaemia group and normal glucose tolerance group, but it was comparable between isolated-impaired fasting glycemia group and normal glucose tolerance group. The prevalence of MAU and the odds ratio for MAU with adjustment for age and sex in various glucose tolerance groups showed the same trend as the UAER. (ii) After adjusting for age and sex, there is a significant association between logUAER and independent risk factors (partial correlation coefficients: r = 0.26 for 2-h post-challenge blood glucose, r = 0.26 for systolic blood pressure, r = 0.27 for diastolic blood pressure, r = 0.27 for body mass index and r = -0.13 for high density lipoprotein-cholesterol, all P < 0.001). The risks for MAU were 2-h post-challenge blood glucose, body mass index and diastolic blood pressure, while high density lipoprotein-cholesterol was protective.

CONCLUSIONS

The urinary albumin excretion rate and prevalence of microalbuminuria were higher in isolated-impaired glucose tolerance subjects than those in isolated-impaired fasting glycaemia subjects. At early abnormal glucose tolerance stage, the increasing post-challenge glycaemia might be a more important risk factor for urinary albumin excretion rate and microalbuminuria than increasing fasting glycaemia.

Angiotensin-converting enzyme gene polymorphism as a potent risk factor for developing microalbuminuria in Japanese patients with type 2 diabetes mellitus: a 9-year follow-up study

To clarify the risk factors for developing microalbuminuria in patients with type 2 diabetes mellitus, a longitudinal observational study was performed. Fifty patients with normoalbuminuria were recruited and treated conventionally for 9 years. Polymorphisms of the angiotensin-converting enzyme (ACE) gene and the angiotensinogen M235T polymorphism were examined. During the study period, 12 of the 50 patients developed microalbuminuria; no patients progressed to macroalbuminuria. Multiple logistic regression analysis was performed using age, duration of diabetes, body mass index, haemoglobin A1c' blood pressure, serum lipid profile and genetic polymorphisms as independent variables and development of microalbuminuria as the dependent variable. The D allele of the ACE gene was an independent and significant variable. We conclude that the ACE gene D allele polymorphism is a potent risk factor for developing microalbuminuria in type 2 diabetic patients.