Blood pressure lowering for the prevention and treatment of diabetic kidney disease

Machine learning prediction models for diabetic kidney disease: systematic review and meta-analysis

BACKGROUND

Machine learning is increasingly recognized as a viable approach for identifying risk factors associated with diabetic kidney disease (DKD). However, the current state of real-world research lacks a comprehensive systematic analysis of the predictive performance of machine learning (ML) models for DKD.

OBJECTIVES

The objectives of this study were to systematically summarize the predictive capabilities of various ML methods in forecasting the onset and the advancement of DKD, and to provide a basic outline for ML methods in DKD.

METHODS

We have searched mainstream databases, including PubMed, Web of Science, Embase, and MEDLINE databases to obtain the eligible studies. Subsequently, we categorized various ML techniques and analyzed the differences in their performance in predicting DKD.

RESULTS

Logistic regression (LR) was the prevailing ML method, yielding an overall pooled area under the receiver operating characteristic curve (AUROC) of 0.83. On the other hand, the non-LR models also performed well with an overall pooled AUROC of 0.80. Our t-tests showed no statistically significant difference in predicting ability between LR and non-LR models (t = 1.6767, p > 0.05).

CONCLUSION

All ML predicting models yielded relatively satisfied DKD predicting ability with their AUROCs greater than 0.7. However, we found no evidence that non-LR models outperformed the LR model. LR exhibits high performance or accuracy in practice, while it is known for algorithmic simplicity and computational efficiency compared to others. Thus, LR may be considered a cost-effective ML model in practice.

Nimbidiol protects from renal injury by alleviating redox imbalance in diabetic mice

Introduction

Chronic hyperglycemia-induced oxidative stress plays a crucial role in the development of diabetic nephropathy (DN). Moreover, adverse extracellular matrix (ECM) accumulation elevates renal resistive index leading to progressive worsening of the pathology in DN. Nimbidiol is an alpha-glucosidase inhibitor, isolated from the medicinal plant, 'neem' (Azadirachta indica) and reported as a promising anti-diabetic compound. Previously, a myriad of studies demonstrated an anti-oxidative property of a broad-spectrum neem-extracts in various diseases including diabetes. Our recent study has shown that Nimbidiol protects diabetic mice from fibrotic renal dysfunction in part by mitigating adverse ECM accumulation. However, the precise mechanism remains poorly understood.

Methods

The present study aimed to investigate whether Nimbidiol ameliorates renal injury by reducing oxidative stress in type-1 diabetes. To test the hypothesis, wild-type (C57BL/6J) and diabetic Akita (C57BL/6-Ins2Akita/J) mice aged 10-14 weeks were used to treat with saline or Nimbidiol (400 μg kg-1 day-1) for 8 weeks.

Results

Diabetic mice showed elevated blood pressure, increased renal resistive index, and decreased renal vasculature compared to wild-type control. In diabetic kidney, reactive oxygen species and the expression levels of 4HNE, p22phox, Nox4, and ROMO1 were increased while GSH: GSSG, and the expression levels of SOD-1, SOD-2, and catalase were decreased. Further, eNOS, ACE2, Sirt1 and IL-10 were found to be downregulated while iNOS and IL-17 were upregulated in diabetic kidney. The changes were accompanied by elevated expression of the renal injury markers viz., lipocalin-2 and KIM-1 in diabetic kidney. Moreover, an upregulation of p-NF-κB and a downregulation of IkBα were observed in diabetic kidney compared to the control. Nimbidiol ameliorated these pathological changes in diabetic mice.

Conclusion

Altogether, the data of our study suggest that oxidative stress largely contributes to the diabetic renal injury, and Nimbidiol mitigates redox imbalance and thereby protects kidney in part by inhibiting NF-κB signaling pathway in type-1 diabetes.

Information Transmission in G Protein-Coupled Receptors

G protein-coupled receptors (GPCRs) are the largest class of receptors in the human genome and constitute about 30% of all drug targets. In this article, intended for a non-mathematical audience, both experimental observations and new theoretical results are compared in the context of information transmission across the cell membrane. The amount of information actually currently used or projected to be used in clinical settings is a small fraction of the information transmission capacity of the GPCR. This indicates that the number of yet undiscovered drug targets within GPCRs is much larger than what is currently known. Theoretical studies with some experimental validation indicate that localized heat deposition and dissipation are key to the identification of sites and mechanisms for drug action.

Candidate composite biomarker to inform drug treatments for diabetic kidney disease

Introduction

Current guidelines recommend renin angiotensin system inhibitors (RASi) as key components of treatment of diabetic kidney disease (DKD). Additional options include sodium-glucose cotransporter-2 inhibitors (SGLT2i), glucagon-like peptide 1 receptor agonists (GLP1a), and mineralocorticoid receptor antagonists (MCRa). The identification of the optimum drug combination for an individual is difficult because of the inter-, and longitudinal intra-individual heterogeneity of response to therapy.

Results

Using data from a large observational study (PROVALID), we identified a set of parameters that can be combined into a meaningful composite biomarker that appears to be able to identify which of the various treatment options is clinically beneficial for an individual. It uses machine-earning techniques to estimate under what conditions a treatment of RASi plus an additional treatment is different from the treatment with RASi alone. The measure of difference is the annual percent change (ΔeGFR) in the estimated glomerular filtration rate (ΔeGFR). The 1eGFR is estimated for both the RASi-alone treatment and the add-on treatment.

Discussion

Higher estimated increase of eGFR for add-on patients compared with RASi-alone patients indicates that prognosis may be improved with the add-on treatment. The personalized biomarker value thus identifies which patients may benefit from the additional treatment.

Effects of sodium-glucose cotransporter 2 inhibitors, mineralocorticoid receptor antagonists, and their combination on albuminuria in diabetic patients

AIMS

Diabetes mellitus (DM) is the leading cause of chronic kidney disease. Albuminuria is associated with an increased risk of cardiovascular mortality. Sodium-glucose cotransporter 2 inhibitors (SGLT2-Is) and mineralocorticoid receptor antagonists (MRAs) protect against albuminuria; however, their combined effects on albuminuria are unclear. We performed a network meta-analysis to investigate the effects of SGLT2-Is, MRAs and their combination on albuminuria in type 2 DM.

METHODS

We systematically searched PubMed, Medline, EMBASE and the Cochrane Library from inception up to 20 November 2022. We selected randomized control and crossover trials that compared MRAs, SGLT2-Is, MRAs + SGLT2-Is, or a placebo in patients with type 2 DM with a urinary albumin-creatinine ratio (UACR) ≥30 mg/g creatinine. The primary outcome was the change in the UACR.

RESULTS

This meta-analysis analysed 17 studies with 34 412 patients. The use of combination treatment with SGLT2-Is and MRAs was associated with lower albuminuria compared with the use of SGLT2-Is, MRAs, or the placebo alone [mean difference (95% CI): -34.19 (-27.30; -41.08), -32.25 (-24.53; -39.97) and -65.22 (-57.97; -72.47), respectively]. Treatment with SGLT2-Is or MRAs alone caused a significant reduction in UACR compared with the placebo [mean difference (95% CI): -31.03 (-28.35; -33.72) and -32.97 (-29.68; -36.27), respectively]. The effects of MRAs on the UACR are comparable with those of SGLT2-Is. Sensitivity analyses showed similar results.

CONCLUSION

Combination therapy with SGLT2-Is and MRAs was associated with lower albuminuria in patients with type 2 DM compared with monotherapy with SGLT2-Is or MRAs alone.

CE: Improving Outcomes for Patients with Chronic Kidney Disease: Part 1

: The burden of chronic kidney disease (CKD) is rising both in this country and worldwide. An estimated 10% to 15% of U.S. adults are currently living with CKD. Reducing the CKD burden requires a systematic, interdisciplinary approach to care. The greatest opportunities to reduce the impact of CKD arise early, when most patients are being followed in primary care; yet many clinicians are inadequately educated on this disease. Nurses are well positioned to facilitate the implementation of collaborative care. This two-part article aims to provide nurses with the basic information necessary to assess and manage patients with CKD. Part 1 offers an overview of the disease, describes identification and etiology, and discusses ways to slow disease progression. Part 2, which will appear next month, addresses disease complications and treatment of kidney failure.

Effect of angiotensin converting enzyme inhibitor on glomerular hyperfiltration in patients with type 1 diabetes

OBJECTIVE

To assess the effect of angiotensin converting enzyme inhibition on glomerular filtration rate (GFR) in normotensive patient with type 1 diabetes.

METHODS

A two year non-placebo control prospective study was conducted after ethical approval at Diabetes Centre of Diabetic Association of Pakistan, a WHO collaborating centre in Karachi, Pakistan. All patients with type 1 diabetes visited the out-patients department from August 2009 till July 2011 and those who fulfilled the inclusion criteria were invited to participate. A total of 121 people aged ≥18 years and ≥ 5 years of diabetes were included. Pregnant and lactating woman and those aged <18 years were excluded. GFR was calculated by using CKD-EPI formula (eGFR) at baseline and after two year. On the basis of estimated GFR, patients at baseline were divided according to KDIGO classification of chronic kidney diseases into, hyperfiltration (eGFR ≥ 100 ml/min) and normal filtration group (eGFR < 100 ml/min). All subjects in hyperfiltration group received ACE inhibitor (treatment group) while patients with normal filtration did not receive ACE inhibitor (control group).

RESULTS

Fifty two patients (43%) were in the treatment and sixty nine (57%) were in the control group. At baseline eGFR, systolic and diastolic blood pressures between groups were non-significantly different. After two years, compared to baseline, eGFR of the treatment group declined and the control group increased significantly. No significant difference in systolic while diastolic blood pressure of the treatment group increased significantly after two years compared to baseline. In contrast both systolic and diastolic blood pressure of control group increased significantly after two years compared to their baseline values.

CONCLUSION

Present study demonstrated that initiation of ACEI in hyperfiltration stage declined GFR and keep blood pressure within normal range.

Tofogliflozin, a novel sodium-glucose co-transporter 2 inhibitor, improves renal and pancreatic function in db/db mice

BACKGROUND AND PURPOSE

Although inhibition of renal sodium-glucose co-transporter 2 (SGLT2) has a stable glucose-lowering effect in patients with type 2 diabetes, the effect of SGLT2 inhibition on renal dysfunction in type 2 diabetes remains to be determined. To evaluate the renoprotective effect of SGLT2 inhibition more precisely, we compared the effects of tofogliflozin (a specific SGLT2 inhibitor) with those of losartan (an angiotensin II receptor antagonist) on renal function and beta-cell function in db/db mice.

EXPERIMENTAL APPROACH

The effects of 8-week tofogliflozin or losartan treatment on renal and beta-cell function were investigated in db/db mice by quantitative image analysis of glomerular size, mesangial matrix expansion and islet beta-cell mass. Blood glucose, glycated Hb and insulin levels, along with urinary albumin and creatinine were measured

KEY RESULTS

Tofogliflozin suppressed plasma glucose and glycated Hb and preserved pancreatic beta-cell mass and plasma insulin levels. No improvement of glycaemic conditions or insulin level was observed with losartan treatment. Although the urinary albumin/creatinine ratio of untreated db/db mice gradually increased from baseline, tofogliflozin or losartan treatment prevented this increase (by 50-70%). Tofogliflozin, but not losartan, attenuated glomerular hypertrophy. Neither tofogliflozin nor losartan altered matrix expansion.

CONCLUSIONS AND IMPLICATIONS

Long-term inhibition of renal SGLT2 by tofogliflozin not only preserved pancreatic beta-cell function, but also prevented kidney dysfunction in a mouse model of type 2 diabetes. These findings suggest that long-term use of tofogliflozin in patients with type 2 diabetes may prevent progression of diabetic nephropathy.

Chronic bilateral renal denervation attenuates renal injury in a transgenic rat model of diabetic nephropathy

Bilateral renal denervation (BRD) has been shown to reduce hypertension and improve renal function in both human and experimental studies. We hypothesized that chronic intervention with BRD may also attenuate renal injury and fibrosis in diabetic nephropathy. This hypothesis was examined in a female streptozotocin-induced diabetic (mRen-2)27 rat (TGR) shown to capture the cardinal features of human diabetic nephropathy. Following diabetic induction, BRD/sham surgeries were conducted repeatedly (at the week 3, 6, and 9 following induction) in both diabetic and normoglycemic animals. Renal denervation resulted in a progressive decrease in systolic blood pressure from first denervation to termination (at 12 wk post-diabetic induction) in both normoglycemic and diabetic rats. Renal norepinephrine content was significantly raised following diabetic induction and ablated in denervated normoglycemic and diabetic groups. A significant increase in glomerular basement membrane thickening and mesangial expansion was seen in the diabetic kidneys; this morphological appearance was markedly reduced by BRD. Immunohistochemistry and protein densitometric analysis of diabetic innervated kidneys confirmed the presence of significantly increased levels of collagens I and IV, α-smooth muscle actin, the ANG II type 1 receptor, and transforming growth factor-β. Renal denervation significantly reduced protein expression of these fibrotic markers. Furthermore, BRD attenuated albuminuria and prevented the loss of glomerular podocin expression in these diabetic animals. In conclusion, BRD decreases systolic blood pressure and reduces the development of renal fibrosis, glomerulosclerosis, and albuminuria in this model of diabetic nephropathy. The evidence presented strongly suggests that renal denervation may serve as a therapeutic intervention to attenuate the progression of renal injury in diabetic nephropathy.

Meta-analysis of three observational studies of amlodipine/valsartan in hypertensive patients with additional risk factors

OBJECTIVES

In this study, the effectiveness of amlodipine/valsartan single-pill combination was assessed in hypertensive patients with diabetes, metabolic risk or overweight.

METHODS

Data from 12,265 patients treated with amlodipine/valsartan from three studies were analyzed in a meta-analysis. These studies focused on (i) non-diabetic hypertensive patients suffering from abdominal obesity; (ii) hypertensive patients with at least one metabolic risk factor; and (iii) hypertensive patients with type 2 diabetes mellitus. The observation periods were 16 weeks for the first two and 24 weeks for the latter cohort.

RESULTS

At start of observation, the mean blood pressure was 162.3 mmHg (systolic) and 93.5 mmHg (diastolic). A total of 7.4% of patients were aged ≥ 80 years. At end of the observation, a normalized blood pressure was present in 38.8% of patients. No appreciable differences in blood pressure reduction were evident between the study groups. In both age subgroups (< 80 years and ≥ 80 years) blood pressure reduction was comparable. Tolerability was assessed by treating physicians as "very good" (69.3%) and "good" (27.3%).

CONCLUSIONS

In daily practice, treatment of hypertensive patients with additional risk factors with amlodipine/valsartan single-pill combinations is well tolerated and associated with effective reduction of blood pressure.

Potential drug interactions associated with treatments for type 2 diabetes and its comorbidities: a clinical pharmacology review

Type 2 diabetes is a disease of glucose metabolism that commonly involves multiple comorbidities, including lipid dyscrasias and hypertension. Each concurrent disorder contributes some risk of complications and requires therapeutic intervention. The simultaneous management of so many coexisting illnesses can be complex and commonly results in patients being prescribed multiple medications--referred to as polypharmacy--which may further complicate treatment. To ensure the best patient outcomes, the treating physician must be aware of all the therapeutic agents that a patient is taking to assess possible drug interactions that such a plethora of medications may confer. This article addresses the underlying comorbidites, the drugs commonly used to treat them and the interactions that may arise from concomitant administration.

Tight blood pressure control in diabetes: evidence-based review of treatment targets in patients with diabetes

Blood pressure (BP) targets in diabetic patients stills represent the object of a major debate, fueled by the recent publication of post hoc observational analyses of the INVEST and the ONTARGET trials, suggesting an increased risk of cardiovascular events with tighter control, the J-curve effect, and by the results of the ACCORD trial, showing no improvements in the composite primary outcome of nonfatal myocardial infarction, stroke, or cardiovascular death in the intensive BP-lowering arm (<120/80 mmHg). In the present review, we focus on existing evidence about different BP targets in diabetic subjects and we present the results of our recent meta-analysis, showing that tight BP control may significantly reduce the risk of stroke in these patients without increasing the risk of myocardial infarction. Therapeutic inertia (leaving diabetic patients with BP values of 140/90 mmHg or higher) should be avoided at all costs, as this would lead to an unacceptable toll in terms of human lives, suffering, and socioeconomic costs.

Discovery of early-stage biomarkers for diabetic kidney disease using ms-based metabolomics (FinnDiane study)

Diabetic kidney disease (DKD) is a devastating complication that affects an estimated third of patients with type 1 diabetes mellitus (DM). There is no cure once the disease is diagnosed, but early treatment at a sub-clinical stage can prevent or at least halt the progression. DKD is clinically diagnosed as abnormally high urinary albumin excretion rate (AER). We hypothesize that subtle changes in the urine metabolome precede the clinically significant rise in AER. To test this, 52 type 1 diabetic patients were recruited by the FinnDiane study that had normal AER (normoalbuminuric). After an average of 5.5 years of follow-up half of the subjects (26) progressed from normal AER to microalbuminuria or DKD (macroalbuminuria), the other half remained normoalbuminuric. The objective of this study is to discover urinary biomarkers that differentiate the progressive form of albuminuria from non-progressive form of albuminuria in humans. Metabolite profiles of baseline 24 h urine samples were obtained by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) to detect potential early indicators of pathological changes. Multivariate logistic regression modeling of the metabolomics data resulted in a profile of metabolites that separated those patients that progressed from normoalbuminuric AER to microalbuminuric AER from those patients that maintained normoalbuminuric AER with an accuracy of 75% and a precision of 73%. As this data and samples are from an actual patient population and as such, gathered within a less controlled environment it is striking to see that within this profile a number of metabolites (identified as early indicators) have been associated with DKD already in literature, but also that new candidate biomarkers were found. The discriminating metabolites included acyl-carnitines, acyl-glycines and metabolites related to tryptophan metabolism. We found candidate biomarkers that were univariately significant different. This study demonstrates the potential of multivariate data analysis and metabolomics in the field of diabetic complications, and suggests several metabolic pathways relevant for further biological studies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-011-0291-6) contains supplementary material, which is available to authorized users.

NF-κB activation in organs from STZ-treated rats

Nuclear factor kappa B (NF-κB) is a ubiquitously expressed transcription factor comprised of various subunits (p50 (NF-κB1), p52 (NF-κB2), p65 (RelA), RelB, and c-Rel). Activation of certain NF-κB subunits appears to foster an inflammatory state that may promote the development of disease. Thus characterizing the specific NF-κB subunits may provide insight into the pathogenesis of certain diseases. The purpose of this study was to determine if 1 month of a diabetic state, induced by streptozotocin (STZ) treatment, alters the constitutive level of NF-κB activation, its subunit composition, or the content of NF-κB-related proteins in rodent liver, kidney, spleen, and heart. Diabetes was induced in male Sprague-Dawley rats by a single tail vein injection of STZ (55 mg·kg-1 body weight). After 30 days, the heart, liver, spleen, and kidney were assessed for NF-κB activation and subunit composition with electrophoretic mobility shift assay (EMSA), and p50 and p65 subunit content was assessed with Western blotting. In diabetic animals, the constitutive level of NF-κB activation was reduced in liver, but was unchanged in kidney, spleen, and heart. EMSA supershifts showed the predominant subunit in the activated NF-κB complexes from both diabetic and control animals to be p50, although the p65 subunit was detected in NF-κB complexes from diabetic hearts. The content of p50 was unaltered in all diabetic tissues examined, whereas the content of p65 was increased only in hearts from diabetic animals. These findings support the idea that a diabetic state may induce specific changes in NF-κB subunit composition in certain tissues.

The contribution of hypertension to diabetic nephropathy and retinopathy: the role of inflammation and oxidative stress

Diabetes and hypertension frequently coexist and constitute the most notorious combination for the pathogenesis of diabetic nephropathy and retinopathy. Large clinical trials have clearly demonstrated that tight control of glycemia and/or blood pressure significantly reduces the incidence and progression of diabetic retinopathy (DR) and nephropathy. However, the mechanism by which hypertension interacts with diabetes to induce and/or exacerbate nephropathy and retinopathy is very unclear. Substantial evidence implicates the involvement of chronic inflammation and oxidative stress in the pathogenesis of DR and nephropathy. In addition, hypertension causes oxidative stress and inflammation in the kidney and retina. In the present review, we summarized data obtained from our research along with those from other groups to better understand the role of hypertension in the pathogenesis of diabetic nephropathy and retinopathy. It is suggested that oxidative stress and inflammation may be common denominators of kidney and retinal damage in the concomitant presence of diabetes and hypertension.

Network of vascular diseases, death and biochemical characteristics in a set of 4,197 patients with type 1 diabetes (the FinnDiane Study)

Background

Cardiovascular disease is the main cause of premature death in patients with type 1 diabetes. Patients with diabetic kidney disease have an increased risk of heart attack or stroke. Accurate knowledge of the complex inter-dependencies between the risk factors is critical for pinpointing the best targets for research and treatment. Therefore, the aim of this study was to describe the association patterns between clinical and biochemical features of diabetic complications.

Methods

Medical records and serum and urine samples of 4,197 patients with type 1 diabetes were collected from health care centers in Finland. At baseline, the mean diabetes duration was 22 years, 52% were male, 23% had kidney disease (urine albumin excretion over 300 mg/24 h or end-stage renal disease) and 8% had a history of macrovascular events. All-cause mortality was evaluated after an average of 6.5 years of follow-up (25,714 patient years). The dataset comprised 28 clinical and 25 biochemical variables that were regarded as the nodes of a network to assess their mutual relationships.

Results

The networks contained cliques that were densely inter-connected (r > 0.6), including cliques for high-density lipoprotein (HDL) markers, for triglycerides and cholesterol, for urinary excretion and for indices of body mass. The links between the cliques showed biologically relevant interactions: an inverse relationship between HDL cholesterol and the triglyceride clique (r < -0.3, P < 10^-16), a connection between triglycerides and body mass via C-reactive protein (r > 0.3, P < 10^-16) and intermediate-density cholesterol as the connector between lipoprotein metabolism and albuminuria (r > 0.3, P < 10^-16). Aging and macrovascular disease were linked to death via working ability and retinopathy. Diabetic kidney disease, serum creatinine and potassium, retinopathy and blood pressure were inter-connected. Blood pressure correlations indicated accelerated vascular aging in individuals with kidney disease (P < 0.001).

Conclusion

The complex pattern of links between diverse characteristics and the lack of a single dominant factor suggests a need for multifactorial and multidisciplinary paradigms for the research, treatment and prevention of diabetic complications.

The presence and severity of chronic kidney disease predicts all-cause mortality in type 1 diabetes

OBJECTIVES

This study aimed to identify clinical features associated with premature mortality in a large contemporary cohort of adults with type 1 diabetes.

RESEARCH DESIGN AND METHODS

The Finnish Diabetic Nephropathy (FinnDiane) study is a national multicenter prospective follow-up study of 4,201 adults with type 1 diabetes from 21 university and central hospitals, 33 district hospitals, and 26 primary health care centers across Finland.

RESULTS

During a median 7 years of follow-up, there were 291 deaths (7%), 3.6-fold (95% CI 3.2-4.0) more than that observed in the age- and sex-matched general population. Excess mortality was only observed in individuals with chronic kidney disease. Individuals with normoalbuminuria showed no excess mortality beyond the general population (standardized mortality ratio [SMR] 0.8, 95% CI 0.5-1.1), independent of the duration of diabetes. The presence of microalbuminuria, macroalbuminuria, and end-stage kidney disease was associated with 2.8, 9.2, and 18.3 times higher SMR, respectively. The increase in mortality across each stage of albuminuria was equivalent to the risk conferred by preexisting macrovascular disease. In addition, the glomerular filtration rate was independently associated with mortality, such that individuals with impaired kidney function, as well as those demonstrating hyperfiltration, had an increased risk of death.

CONCLUSIONS

An independent graded association was observed between the presence and severity of kidney disease and mortality in a large contemporary cohort of individuals with type 1 diabetes. These findings highlight the clinical and public health importance of chronic kidney disease and its prevention in the management of type 1 diabetes.

Choice of ACE inhibitor combinations in hypertensive patients with type 2 diabetes: update after recent clinical trials

The diabetes epidemic continues to grow unabated, with a staggering toll in micro- and macrovascular complications, disability, and death. Diabetes causes a two- to fourfold increase in the risk of cardiovascular disease, and represents the first cause of dialysis treatment both in the UK and the US. Concomitant hypertension doubles total mortality and stroke risk, triples the risk of coronary heart disease and significantly hastens the progression of microvascular complications, including diabetic nephropathy. Therefore, blood pressure reduction is of particular importance in preventing cardiovascular and renal outcomes. Successful antihypertensive treatment will often require a combination therapy, either with separate drugs or with fixed-dose combinations. Angiotensin converting enzyme (ACE) inhibitor plus diuretic combination therapy improves blood pressure control, counterbalances renin-angiotensin system activation due to diuretic therapy and reduces the risk of electrolyte alterations, obtaining at the same time synergistic antiproteinuric effects. ACE inhibitor plus calcium channel blocker provides a significant additive effect on blood pressure reduction, may have favorable metabolic effects and synergistically reduce proteinuria and the rate of decline in glomerular filtration rate, as evidenced by the GUARD trial. Finally, the recently published ACCOMPLISH trial showed that an ACE inhibitor/calcium channel blocker combination may be particularly useful in reducing cardiovascular outcomes in high-risk patients. The present review will focus on different ACE inhibitor combinations in the treatment of patients with type 2 diabetes mellitus and hypertension, in the light of recent clinical trials, including GUARD and ACCOMPLISH.

Kidney pathological changes in metabolic syndrome: a cross-sectional study

BACKGROUND

The worldwide prevalence of metabolic syndrome is increasing and has been associated with chronic kidney disease. Kidney pathological findings in patients with metabolic syndrome have not been well described, as was explored in this study.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

We retrospectively screened clinical information for 146 patients who underwent elective nephrectomy for renal cell carcinoma between January 2005 and March 2007 at Brigham and Women's Hospital, Boston, MA. Twelve patients with metabolic syndrome were identified. Twelve age- and sex-matched patients who did not have any of the criteria for metabolic syndrome were used as controls.

PREDICTOR

Presence of metabolic syndrome defined by using Adult Treatment Panel III criteria.

OUTCOMES

Histological characteristics in each group, decrease in kidney function at 1-year follow-up.

MEASUREMENTS

Two pathologists blinded to the clinical diagnosis independently evaluated nephrectomy specimens using Banff criteria to objectively assess histological characteristics.

RESULTS

Baseline characteristics were similar between the 2 groups. On histopathologic examination, patients with metabolic syndrome compared with controls had a greater prevalence of tubular atrophy (P = 0.006), interstitial fibrosis (P = 0.001), and arterial sclerosis (P = 0.001), suggesting microvascular disease. Patients with metabolic syndrome had greater global (P = 0.04) and segmental glomerulosclerosis (P = 0.05). Glomerular volume and cross-sectional surface area were not different. The combined end point of tubular atrophy greater than 5%, interstitial fibrosis greater than 5%, and presence of arterial sclerosis was more prevalent in patients with metabolic syndrome (P = 0.003; odds ratio, 33; confidence interval, 2.9 to 374.3) than controls. After 1 year, estimated glomerular filtration rate was significantly lower in patients with metabolic syndrome compared with controls (P = 0.03).

LIMITATIONS

Small sample size, retrospective design.

CONCLUSIONS

We report a high prevalence of microvascular disease in patients with metabolic syndrome. There was a steeper decrease in kidney function over time in patients with metabolic syndrome, suggesting limited renal reserve. Aggressive screening and management may be warranted in patients with metabolic syndrome to protect kidney function.

Assessment and management of hypertension in patients with type 2 diabetes

BACKGROUND

Hypertension is a major risk factor for adverse outcomes in type 2 diabetes and an important target for intervention. Despite this, the management of blood pressure (BP) remains suboptimal, particularly in patients at increased risk for cardiovascular and chronic kidney disease. The aim of this study was to estimate the frequency of hypertension and its management in consecutive clinic-based samples of patients with type 2 diabetes in Australian primary care.

METHODS

BP levels and antihypertensive management strategies were compared in patients with type 2 diabetes recruited as part of the Developing Education on Microalbuminuria for Awareness of reNal and cardiovascular risk in Diabetes (DEMAND) study in 2003 (n = 1831) and the National Evaluation of the Frequency of Renal impairment cO-existing with Non-insulin-dependent diabetes (NEFRON) study in 2005 (n = 3893). Systolic BP levels and the use of antihypertensive therapies were examined in patients with and without chronic kidney disease.

RESULTS

The patient characteristics in both studies were similar in that more than 80% of patients in both studies were hypertensive. Systolic BP targets of < or =130 mmHg were achieved in approximately half of all treated patients in both studies. However, the use of antihypertensive therapy either alone or in combination increased from 70.4% in DEMAND to 79.5% in NEFRON 2 years later (P < 0.001). Despite this, antihypertensive therapy continued to be underutilized in high-risk groups, including in those with established chronic kidney disease.

CONCLUSION

The DEMAND and NEFRON studies both show that BP control is achievable in Australian general practice, with more than half of all patients seeing their general practitioners achieving a target systolic BP < or =130 mmHg. However, more needs to be done to further reduce BP levels, particularly in patients at high risk of adverse outcomes.

LR-90 prevents dyslipidaemia and diabetic nephropathy in the Zucker diabetic fatty rat

AIMS/HYPOTHESIS

Previous studies have shown that LR-90, a new inhibitor of AGE formation, prevented the development of experimental type 1 diabetic nephropathy. In this study, we examined the effects of LR-90 in the Zucker diabetic fatty (ZDF) rat, a model of type 2 diabetes and metabolic syndrome, and investigated the mechanisms by which it may protect against renal injury.

METHODS

Male ZDF rats were treated without or with LR-90 from age 13 to 40 weeks. Metabolic and kidney functions and renal histology were evaluated. AGE accumulation and the production of the receptor for AGE (AGER) were measured. Profibrotic growth factors, extracellular matrix proteins and intracellular signalling pathways associated with glomerular and tubular damage were also analysed.

RESULTS

LR-90 dramatically reduced plasma lipids in ZDF rats, with only modest effects on hyperglycaemia. Renal AGE, AGER and lipid peroxidation were all attenuated by LR-90. LR-90 significantly retarded the increase in albuminuria and proteinuria. This was associated with reduction in glomerulosclerosis and tubulointerstitial fibrosis, concomitant with marked inhibition of renal overproduction of TGF-beta1, connective tissue growth factor, fibronectin and collagen IV. Additionally, LR-90 downregulated the activation of key mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-kappaB) in the renal cortex.

CONCLUSIONS/INTERPRETATION

These results support our earlier studies on the renoprotective effects of LR-90 on type 1 diabetic nephropathy and provide further evidence that LR-90, an AGE inhibitor with pleiotrophic effects, may also be beneficial for the prevention of type 2 diabetic nephropathy, where multiple risk factors, such as hyperglycaemia, dyslipidaemia, obesity, insulin resistance and hypertension, contribute to renal injury.

Conceptual basis and methodology of the SOPHIA study

To clarify the role of gene polymorphisms on the effect of losartan and losartan plus hydrochlorothiazide on blood pressure (primary end point) and on cardiac, vascular and metabolic phenotypes (secondary end point) after 4, 8, 12, 16 and 48 weeks treatment, an Italian collaborative study - The Study of the Pharmacogenomics in Italian hypertensive patients treated with the Angiotensin receptor blocker losartan (SOPHIA) - on never-treated essential hypertensives (n = 800) was planned. After an 8 week run-in, losartan 50 mg once daily will be given and doubled to 100 mg at week +4 if blood pressure is more than 140/90 mmHg. Hydroclorothiazide 25 mg once daily at week +8 and amlodipine 5 mg at week +16 will be added if blood pressure is more than 140/90 mmHg. Cardiac mass (echocardiography), carotid intima-media thickness, 24 h ambulatory blood pressure, homeostatic model assessment (HOMA) index, microalbuminuria, plasma renin activity and aldosterone, endogenous lithium clearance, brain natriuretic peptide and losartan metabolites will be evaluated. Genes of the renin-angiotensin-aldosterone system, salt sensitivity, the beta-adrenergic system and losartan metabolism will be studied (Illumina custom arrays). A whole-genome scan will also be performed in half of the study cohort (1M array, Illumina 500 GX beadstation).

1H NMR metabonomics approach to the disease continuum of diabetic complications and premature death

Subtle metabolic changes precede and accompany chronic vascular complications, which are the primary causes of premature death in diabetes. To obtain a multimetabolite characterization of these high-risk individuals, we measured proton nuclear magnetic resonance (1H NMR) data from the serum of 613 patients with type I diabetes and a diverse spread of complications. We developed a new metabonomics framework to visualize and interpret the data and to link the metabolic profiles to the underlying diagnostic and biochemical variables. Our results indicate complex interactions between diabetic kidney disease, insulin resistance and the metabolic syndrome. We illustrate how a single 1H NMR protocol is able to identify the polydiagnostic metabolite manifold of type I diabetes and how its alterations translate to clinical phenotypes, clustering of micro- and macrovascular complications, and mortality during several years of follow-up. This work demonstrates the diffuse nature of complex vascular diseases and the limitations of single diagnostic biomarkers. However, it also promises cost-effective solutions through high-throughput analytics and advanced computational methods, as applied here in a case that is representative of the real clinical situation.

Prevention of Hypertension with or without Renin-Angiotensin System Inhibition Precludes Nephrin Loss in the Early Stage of Experimental Diabetes Mellitus

BACKGROUND AND AIMS

Several lines of clinical evidence support the concept that the reduction of blood pressure may be useful in the prevention of diabetic kidney disease. In young diabetic spontaneously hypertensive rats (SHR), prevention of hypertension reduces several early renal abnormalities including albuminuria. However, the contribution of nephrin loss to albuminuria in this early stage of experimental diabetes is unknown. Therefore, we investigated whether elevation of albuminuria in young diabetic SHR is associated with nephrin loss, and if prevention of hypertension, with or without inhibition of the renin-angiotensin system, precludes these abnormalities.

METHODS

Diabetes was induced by streptozotocin injection in 4-week-old still normotensive SHR and their genetically normotensive control, Wistar-Kyoto rats. Diabetic SHR were randomized for no treatment, or treatment with captopril, losartan, or triple therapy (hydrochlorothiazide, reserpine and hydralazine) for 20 days.

RESULTS

The increase in systolic blood pressure was equally prevented by all treatments. Albuminuria was higher in diabetic SHR and similarly reduced (p < 0.05) by captopril, losartan, and triple therapy. Glomerular expression of nephrin was significantly reduced in diabetic SHR in comparison with non-diabetic controls. The antihypertensive treatment prevented the reduction in glomerular expression of nephrin.

CONCLUSIONS

These results demonstrate that the loss of nephrin is associated with albuminuria in a model of genetic hypertension and diabetes, and that the prevention of development of hypertension restores nephrin and prevents albuminuria. This finding suggests a crucial role of blood pressure in diabetes as determinant of nephrin expression and albuminuria.