Regression of albuminuria: latest evidence for a new approach

Prevention of cardiovascular complications of the metabolic syndrome: focus on pharmacotherapy

The metabolic syndrome increases the risk of atherothrombotic cardiovascular disease (CVD) and diabetes. In turn, diabetes promotes the development of atheroma and is regarded as a coronary heart disease risk equivalent. A multifactorial therapeutic strategy is advocated for patients with the metabolic syndrome to improve cardiovascular risk factor profiles and to reduce the chances of developing type 2 diabetes. Individual components of the syndrome must be addressed using safe, efficacious, and cost-effective measures. There is general agreement that lifestyle modifications, including control of body weight, avoidance of central adiposity, adoption of an antiatherogenic diet, and regular physical activity, are crucial. However, as the magnitude of the individual components of the metabolic syndrome increases with time, lifestyle measures are often insufficient. An individual with metabolic syndrome will often require drug treatment for hyperglycemia, atherogenic dyslipidemia, and high blood pressure, together with antiplatelet therapy. Reducing the need for polypharmacy is an increasingly important consideration for clinicians and the pharmaceutical industry; to date, no single therapy has emerged that targets the root cause(s) of the syndrome. HMG-CoA reductase inhibitors are important agents that reduce CVD morbidity and mortality, in people with impaired fasting glucose or metabolic syndrome. Selective cannabinoid receptor antagonists appear promising because they improve or attenuate several key defects of the syndrome. Thiazolidinediones and metformin are presently licensed for treatment of type 2 diabetes but may prove to have a broader role in future. Novel insulin-sensitizing drugs are under investigation. Drugs that act to prevent or reverse endothelial dysfunction may be of particular utility in preventing cardiovascular disease, especially if initiated before tissue damage has become irreversible. Insulin therapy, which has antiinflammatory and endothelial protective properties, has been shown to reduce morbidity and mortality in high-risk nondiabetic patients during critical illness. Potential synergy between different classes of drugs with metabolic and/or cardiovascular protective properties merits further investigation.

Protein and albumin-to-creatinine ratios in random urines accurately predict 24 h protein and albumin loss in patients with kidney disease

BACKGROUND

Random urine protein-to-creatinine (PCR) and albumin-to-creatinine (ACR) ratios have been proposed as alternatives to 24 h urine measurements to simplify sample collection and overcome errors. The aim of this study was to examine the ability of PCR and ACR to predict urinary 24 h protein and albumin loss, respectively, in patients with kidney disease, and determine the most appropriate time of collection.

METHODS

Eighty-three patients were recruited from a renal outpatient clinic. In a 24 h period, each collected an early-morning urine (EMU), second and third voids, and the remaining urine passed that day. PCR and ACR were determined in random urines and compared with the 24 h loss of protein and albumin, respectively.

RESULTS

For all patients, median (range) 24 h urine protein and albumin losses were 220 (30-15600) and 60 (<8-10,557) mg, respectively. Ratios derived from each of three random urines correlated well with 24 h protein or albumin loss (Spearman's r(s) > 0.87, P < 0.0001). Receiver operator characteristic (ROC) curve analysis showed PCR accurately predicted both an abnormal 24 h urine protein > or =150 mg/24 h (areas under curves [AUC] 0.90-0.92) and significant proteinuria above 300 mg/24 h (AUC between 0.97 and 1.00). ACR accurately predicted both an abnormal 24 h urine albumin > or =30 mg/24 h (AUC 0.98 to 0.99) and frank albuminuria at > or =300 mg/24 h or > or =700 mg/24 h (AUC between 0.99 and 1.00). EMU and random urines performed equally well in predicting proteinuria and albuminuria from PCR and ACR, respectively.

CONCLUSIONS

By careful choice of cut-offs, both PCR and ACR can be used in patients with kidney disease to rule in or rule out abnormal 24 h losses of protein and albumin. EMU and, importantly, random samples can be used as surrogates for 24 h urine collections.

Statins, ACE inhibitors and ARBs in cardiovascular disease

Atherosclerotic cardiovascular disease (CVD) is the main cause of death in developed and developing countries. It is well accepted that several diseases - including hypertension, dyslipidemia and diabetes mellitus - increase CVD. More recently also chronic inflammatory diseases, such as rheumatoid arthritis, have been shown to accelerate CVD. This association further supports a responsible role for inflammatory processes in all stages of CVD pathophysiology. Clinically, CVD ranges through different acute and chronic syndromes with ischemic symptoms in distal tissues, including heart, cerebral region or peripheral arteries. Several treatments for reducing CVD are under investigation. In this review we focus on statins, angiotensin-converting-enzyme (ACE) inhibitors, and angiotensin-II receptor blockers (ARBs), updating therapeutic evidence from the last clinical trials with particular relevance to diabetic patients.

Phosphoinositide 3-kinase contributes to diabetes-induced abnormal vascular reactivity in rat perfused mesenteric bed

Phosphatidylinositol 3-kinase (PI3K) is a signaling enzyme that plays key roles in vascular growth, proliferation, and cellular apoptosis and is implicated in modulating vascular smooth muscle contractility. The aim of this study was to determine whether PI3K contributes to development of diabetes-induced abnormal vascular reactivity to selected vasoactive agonists. The effect of 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), a selective PI3K inhibitor, on isolated perfused mesenteric vascular bed from streptozotocin (STZ)-diabetic rats was investigated. Changes in perfusion pressure, which reflected peripheral resistance, were measured using isolated perfused mesenteric vascular beds. Our results showed that STZ treatment produced an increase in the vasoconstrictor response to norepinephrine (NE), angiotensin II (Ang II) and endothelin-1 (ET-1), and an attenuated vasodilator response to carbachol and histamine in the isolated perfused mesenteric vascular bed from STZ-diabetic animals. Chronic inhibition of PI3K with LY294002 resulted in prevention of diabetes-induced abnormal vascular reactivity to the vasoactive agonists. However, the high blood glucose levels were not normalized. Results of this study indicate that selective inhibition of PI3K can attenuate the development of diabetes-induced abnormal vascular responsiveness in the isolated perfused mesenteric vascular bed.

Thiazolidinediones and diabetic nephropathy: need for a closer examination?

Diabetic nephropathy is an important public health issue and a major challenge for modern nephrology, as it is the primary cause of end-stage renal disease. In addition to established risk factors for diabetic nephropathy progression (ie, hyperglycemia and hypertension), current knowledge suggests that other factors can be involved. Population studies show that insulin resistance and hyperinsulinemia are also associated with chronic kidney disease, and several background mechanisms could explain this relationship. The hypoglycemic class of thiazolidinediones that act through reduction of insulin resistance were found to protect against renal injury in diabetic animals and to reduce urinary albumin excretion in patients with type 2 diabetes and microalbuminuria. This renoprotective action is supported by relevant studies showing that thiazolidinediones act beneficially on most of the players involved in diabetic nephropathy progression. Recent studies have raised uncertainty about the cardiovascular safety of thiazolidinediones. After the latter issue is resolved, however, it would appear very interesting to conduct specific studies in patients with overt diabetic nephropathy to determine the effect of these agents on proteinuria and kidney disease progression.

Microalbuminuria in Thai essential hypertensive patients

Essential hypertensive patients (176 males and 329 females), aged 58.0+/-11.2 years were enrolled in a cross-sectional study conducted from February to March 2006 to investigate the prevalence and risk factors for microalbuminuria in hypertensive patients attending the Outpatient Department of Siriraj Hospital, Bangkok, Thailand. Macroalbuminuria was detected in 11 (2.2%) patients and microalbuminuria in 94 (18.6%) patients. Only male aged>or=45 years or female aged>or=55 years correlated significantly with a high occurrence of microalbuminuria, while calcium channel blocker and statin users were protected against microalbuminuria. The presence of microalbuminuria was not associated with age>or=60 years, male gender, current/previous smokers, hypertension duration>or=10 years, lack of blood pressure normalization, metabolic syndrome, use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and multi-drug use. Risk factor recognition for microalbuminuria will enable physicians to identify cases that should be screened for microalbuminuria.

Effect of sulodexide on albuminuria, NAG excretion and glomerular filtration response to dopamine in diabetic patients

BACKGROUND

Albuminuria is the best and most readily available marker for glomerular damage and progressive renal function loss in patients with diabetic nephropathy. Recently, administration of the oral glycosaminoglycan sulodexide (a mixture of 80% fast-moving heparin and 20% dermatan sulphate) was shown to effectively decrease albumin excretion rate in diabetics with nephropathy.

AIMS

To evaluate whether the hypoalbuminuric effect of sulodexide is associated with improvement of the renal vascular or tubule function.

METHODS

Forty-five type 1 diabetic patients, affected by diabetic nephropathy with albuminuria for at least 5 years, were randomly allocated to sulodexide or untreated. Those allocated to sulodexide were given 100 mg of sulodexide daily for 120 days. Renal vascular function (DIR) and N-acetyl-beta-D-glucosaminidase (NAG) excretion were estimated before and at the end of the study, the former in thesulodexide group only. DIR was measured as two Cr(cl) lasting 120 min (before and during 2 mug/kg b.w. i.v. dopamine).

RESULTS

The analysis of trends during the study demonstrated a marked reduction of albuminuria in the sulodexide group (from 126.1 +/- 15.41 to 93.6 +/- 13.7 mg/day). DIR rose from 13.2 +/- 2.1% to 15.44 +/- 1.9% (relative increase: +16.9%), and NAG excretion showed a decreasing trend decreased in the sulodexide group only (from 5.1 +/- 0.62 to 4.7 +/- 0.40 U/g(creat)).

CONCLUSION

The findings presented in this study indicate for the first time that orally available sulodexide may favorably affect the renal vascular function in type 1 diabetic patients with nephropathy and microalbuminuria. The effect of sulodexide on NAG is strongly influenced by the baseline NAG values, with a significant NAG reduction in the patients with the highest baseline NAG values.

Protection of the kidney by thiazolidinediones: An assessment from bench to bedside

The global epidemic of diabetes mellitus has led to a continuous increase in the prevalence of diabetic nephropathy over the past years. Thus, diabetic nephropathy is currently the number one cause of end-stage renal disease in the Western world. It represents a major public health problem for which more effective prevention and treatment strategies are needed. Thiazolidinediones (TZDs) are a class of agents that lower blood glucose through reduction of insulin resistance in patients with type 2 diabetes. Growing evidence support the concept that TZDs have several beneficial effects on the cardiovascular system beyond their effects on glycemic control. These benefits include: blood pressure lowering, triglyceride reduction, high-density lipoprotein-cholesterol elevation, and reduction in subclinical vascular inflammation. Moreover, data from several animal and human studies support the notion that TZDs reduce urine albumin excretion and may prevent development of renal injury. The relative lack of evidence, however, demonstrating the effects of TZDs on hard renal outcomes mandates the need for well-designed trials with this particular objective. This paper summarizes all the data from clinical and experimental studies relevant to a possible renoprotective effect of TZDs and discusses actions of these compounds that may contribute toward this effect.

Development, progression, and regression of microalbuminuria in Japanese patients with type 2 diabetes under tight glycemic and blood pressure control: the Kashiwa study

OBJECTIVE

The goal of this study was to know the fate of albuminuria in Japanese patients with type 2 diabetes under tight blood pressure and glycemic control.

RESEARCH DESIGN AND METHODS

Patients having normoalbuminuria (urinary albumin excretion <30 mg/g creatinine, n = 179) or microalbuminuria (albumin excretion 30-299 mg/g creatinine, n = 94) at baseline have been followed up for 8 years: ratio of men to women was 160/113, the mean age was 58 years, pretreatment HbA(1c) (A1C) was 8.8%, and blood pressure was 136/76 mmHg. A1C <6.5% and blood pressure <130/80 mmHg were targeted, and the A1C of 6.5 +/- 0.7% (mean +/- SD) and blood pressure of 127 +/- 11/72 +/- 6 mmHg have been maintained during the 8 years. Development of microalbuminuria or macroalbuminuria (albumin excretion > or =300 mg/g creatinine) in initially normoalbuminuric patients and progression to macroalbuminuria or regression to normoalbuminuria in initially microalbuminuric patients were assessed at year 8.

RESULTS

Development occurred in 27 (15%) of the normoalbuminuric patients and progression and regression in 16 (17%) and 20 (21%), respectively, of the microalbuminuric patients. Significant independent relationships existed between development and higher achieved mean systolic blood pressure (SBP) and regression and lower achieved mean SBP. In the patients with achieved mean SBP <120 mmHg, development was 3%, progression was 11%, and regression was 44% during 8 years. Prediction for nephropathy by blood pressure and glycemia alone was limited. Nevertheless, albumin excretion at year 8 was positively correlated with achieved mean SBP and baseline albuminuria.

CONCLUSIONS

Development and progression were low and regression was high with SBP of 120 mmHg, provided A1C was maintained at 6.5%.