The kidney in type 2 diabetes therapy

Low glycemic index potato biscuits alleviate physio-histological damage and gut dysbiosis in rats with type-2 diabetes mellitus induced by high-sugar and high-fat diet and streptozotocin

Type 2 diabetes mellitus (T2DM) is the most common type of diabetes globally and poses a major concern for human health. This study aimed to investigate the effects on T2DM of low-glycemic index (GI) potato biscuits with oat bran and inulin as functional additives. T2DM was induced in rats by streptozotocin (STZ) and a high-sugar and high-fat diet. The alleviation of T2DM by low-GI potato biscuits at different doses was evaluated based on the analysis of glycolipid levels, histological observations, inflammatory markers and gut microbiota structure. Compared to wheat biscuits, low-GI potato biscuits resulted in lower postprandial blood glucose levels. After eight weeks of intervention, fasting blood sugar levels were 16.9% lower in T2DM rats fed high-dose low-GI potato biscuits than in untreated T2DM rats. Moreover, the intervention with low-GI potato biscuits significantly alleviated T2DM-induced pathological damage, glucose and lipid metabolic disorders, and inflammation by reversing the levels of total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, transforming growth factor-β, interleukin-1β, interleukin-6 and tumor necrosis factor-α. Moreover, the levels of short-chain fatty acids and gut microbiota structure in T2DM rats were significantly reversed. The abundance of beneficial bacteria (e.g., Bifidobacterium, Lachnoclostridium, Roseburia) in the gut of T2DM rats was significantly increased whereas the abundance of Escherichia-Shigella and Desulfovibrio decreased. The present study revealed that low-GI potato biscuits alleviated damages caused by high-sugar and high-fat diet- and STZ-induced T2DM in rats, as well as reversed disturbances in the gut microbiota. Thus, low-GI potato biscuits are potentially beneficial to T2DM patients.

Impact of magnesium sulfate therapy in improvement of renal functions in high fat diet-induced diabetic rats and their offspring

The role of magnesium sulfate (MgSO₄) administration to prevent diabetic nephropathy (DN) by reducing insulin resistance (IR) and the relationship of this action with gender and the expression of NOX4 and ICAM1 genes in the parents and their offspring were studied. Males and females rat, and their pups were used. Type 2 diabetes induced by high-fat diet (HFD) administration and a low dose of streptozotocin. Animals were divided into the: non-treated diabetic (DC), the diabetic group received insulin (Ins), and the diabetic group received MgSO₄. Two groups of parents received just a normal diet (NDC). Following each set of parents for 16 weeks and their pups for 4 months, while eating normally. We assessed the amount of water consumed, urine volume, and blood glucose level. The levels of glucose, albumin, and creatinine in the urine were also measured, as well as the amounts of sodium, albumin, and creatinine in the serum. Calculations were made for glomerular filtration rate (GFR) and the excretion rates of Na and glucose fractions (FE Na and FE G, respectively). The hyperinsulinemic-euglycemic clamp was done. NOX4 and ICAM1 gene expressions in the kidney were also measured. MgSO₄ or insulin therapy decreased blood glucose, IR, and improved GFR, FE Na, and FE G in both parents and their offspring compared to D group. MgSO₄ improved NOX4 and ICAM1 gene expressions in the parents and their offspring compared to D group. Our results indicated that MgSO₄ could reduce blood glucose levels and insulin resistance, and it could improve kidney function.

Metabolomics Study Reveals the Alteration of Fatty Acid Oxidation in the Heart of Diabetic Mice by Empagliflozin

Empagliflozin (Empa, SGLT2 inhibitor), is widely used in clinical situation for the management of diabetes. It has beneficial effects in reducing cardiac dysfunction and heart failure. However, rare studies had...

Overexpression of lipoic acid synthase gene alleviates diabetic nephropathy of Leprdb/db mice

INTRODUCTION

Diabetic nephropathy (DN) develops in about 40% of patients with type 2 diabetes and remains the leading cause of end-stage renal disease. The mechanisms of DN remain to be elucidated. Oxidative stress is thought to be involved in the development of DN but antioxidant therapy has produced conflicting results. Therefore, we sought to define the role of antioxidant in retarding the development of DN in this study.

RESEARCH DESIGN AND METHODS

We generated a new antioxidant/diabetes mouse model, Lias^H/HLepr^db/db mice, by crossing db/db mice with Lias^H/H mice, which have overexpressed Lias gene (~160%) compared with wild type, and also correspondingly increased endogenous antioxidant capacity. The new model was used to investigate whether predisposed increased endogenous antioxidant capacity was able to retard the development of DN. We systemically and dynamically examined main pathological alterations of DN and antioxidant biomarkers in blood and kidney mitochondria.

RESULTS

Lias^H/HLepr^db/db mice alleviated major pathological alterations in the early stage of DN, accompanied with significantly enhanced antioxidant defense. The model targets the main pathogenic factors by exerting multiple effects such as hypoglycemic, anti-inflammation, and antioxidant, especially protection of mitochondria.

CONCLUSION

The antioxidant animal model is not only very useful for elucidating the underlying mechanisms of DN but also brings insight into a new therapeutic strategy for clinical applications.

An Overview of the Posttranslational Modifications and Related Molecular Mechanisms in Diabetic Nephropathy

Diabetic nephropathy (DN), a common diabetic microvascular complication, is characterized by its complex pathogenesis, higher risk of mortality, and the lack of effective diagnosis and treatment methods. Many studies focus on the diagnosis and treatment of diabetes mellitus (DM) and have reported that the pathophysiology of DN is very complex, involving many molecules and abnormal cellular activities. Given the respective pivotal roles of NF-κB, Nrf2, and TGF-β in inflammation, oxidative stress, and fibrosis during DN, we first review the effect of posttranslational modifications on these vital molecules in DN. Then, we describe the relationship between these molecules and related abnormal cellular activities in DN. Finally, we discuss some potential directions for DN treatment and diagnosis. The information reviewed here may be significant in the design of further studies to identify valuable therapeutic targets for DN.

Perspectives on a Way Forward to Implementation of Precision Medicine in Patients With Diabetic Kidney Disease; Results of a Stakeholder Consensus-Building Meeting

Aim: This study aimed to identify from different stakeholders the benefits and obstacles of implementing precision medicine in diabetic kidney disease (DKD) and to build consensus about a way forward in order to treat, prevent, or even reverse this disease.

Methods: As part of an ongoing effort of moving implementation of precision medicine in DKD forward, a two-day consensus-building meeting was organized with different stakeholders involved in drug development and patient care in DKD, including patients, patient representatives, pharmaceutical industry, regulatory agencies representatives, health technology assessors, healthcare professionals, basic scientists, and clinical academic researchers. The meeting consisted of plenary presentations and discussions, and small group break-out sessions. Discussion topics were based on a symposium, focus groups and literature search. Benefits, obstacles and potential solutions toward implementing precision medicine were discussed. Results from the break-out sessions were presented in plenary and formed the basis of a broad consensus discussion to reach final conclusions. Throughout the meeting, participants answered several statement and open-ended questions on their mobile device, using a real-time online survey tool. Answers to the statement questions were analyzed descriptively. Results of the open-ended survey questions, the break-out sessions and the consensus discussion were analyzed qualitatively.

Results and conclusion: Seventy-one participants from 26 countries attended the consensus-building meeting in Amsterdam, April 2019. During the opening plenary on the first day, the participants agreed with the statement that precision medicine is the way forward in DKD (n = 57, median 90, IQR [75–100]). Lack of efficient tools for implementation in practice and generating robust data were identified as significant obstacles. The identified benefits, e.g., improvement of the benefit-risk ratio of treatment, offer substantive incentives to find solutions for the identified obstacles. Earlier and increased multi-stakeholder collaboration and specific training may provide solutions to alter clinical and regulatory guidelines that lie at the basis of both obstacles and solutions. At the end of the second day, the opinion of the participants toward precision medicine in DKD was somewhat more nuanced (n = 45, median 83, IQR [70–92]) and they concluded that precision medicine is an important way forward in improving the treatment of patients with DKD.

Time for clinical decision support systems tailoring individual patient therapy to improve renal and cardiovascular outcomes in diabetes and nephropathy

The current guideline treatment for patients with diabetes and nephropathy to lower the high risk of renal and cardiovascular (CV) morbidity and mortality is based on results of clinical studies that have tested new drugs in large groups of patients with diabetes and high renal/CV risk. Although this has delivered breakthrough therapies like angiotensin receptor blockers, the residual renal/CV risk remains extremely high. Many subsequent trials have tried to further reduce this residual renal/CV risk, without much success. Post hoc analyses have indicated that these failures are, at least partly, due to a large variability in response between and within the patients. The current ‘group approach’ to designing and evaluating new drugs, as well as group-oriented drug registration and guideline recommendations, does not take this individual response variation into account. Like with antibiotics and cancer treatment, a more individual approach is warranted to effectively optimize individual results. New tools to better evaluate the individual risk change have been developed for improved clinical trial design and to avoid trial failures. One of these tools, the composite multiple parameter response efficacy score , is based on monitoring changes in all available risk factors and integrating them into a prediction of ultimate renal and CV risk reduction. This score has also been modelled into a clinical decision support system for use in monitoring and changing the therapy in individual patients to protect them from renal/CV events. In conclusion, future treatment of renal/CV risk in diabetes should transition from an era of ‘one size fits all’ into the new era of ‘a fit for each size’.

Precision Nephrology Is a Non-Negligible State of Mind in Clinical Research: Remember the Past to Face the Future

CKD is a major public health problem. It is characterized by a multitude of risk factors that, when aggregated, can strongly modify outcome. While major risk factors, namely, albuminuria and low estimated glomerular filtration rate (eGFR) have been well analyzed, a large variability in disease progression still remains. This happens because (1) the weight of each risk factor varies between populations (general population or CKD cohort), countries, and single individuals and (2) response to nephroprotective drugs is so heterogeneous that a non-negligible part of patients maintains a high cardiorenal risk despite optimal treatment. Precision nephrology aims at individualizing cardiorenal prognosis and therapy. The purpose of this review is to focus on the risk stratification in different areas, such as clinical practice, population research, and interventional trials, and to describe the strategies used in observational or experimental studies to afford individual-level evidence. The future of precision nephrology is also addressed. Observational studies can in fact provide more adequate findings by collecting more information on risk factors and building risk prediction models that can be applied to each individual in a reliable fashion. Similarly, new clinical trial designs can reduce the individual variability in response to treatment and improve individual outcomes.

Impact of sex on diabetic nephropathy and the renal transcriptome in UNx db/db C57BLKS mice

Diabetic nephropathy (DN) is associated with albuminuria and loss of kidney function and is the leading cause of end-stage renal disease. Despite evidence of sex-associated differences in the progression of DN in human patients, male mice are predominantly being used in preclinical DN research and drug development. Here, we compared renal changes in male and female uninephrectomized (UNx) db/db C57BLKS mice using immunohistochemistry and RNA sequencing. Male and female UNx db/db mice showed similar progression of type 2 diabetes, as assessed by obesity, hyperglycemia, and HbA1c. Progression of DN was also similar between sexes as assessed by kidney and glomerular hypertrophy as well as urine albumin-to-creatinine ratio being increased in UNx db/db compared with control mice. In contrast, kidney collagen III and glomerular collagen IV were increased only in female UNx db/db as compared with respective control mice but showed a similar tendency in male UNx db/db mice. Comparison of renal cortex transcriptomes by RNA sequencing revealed 66 genes differentially expressed (p < .01) in male versus female UNx db/db mice, of which 9 genes were located on the sex chromosomes. In conclusion, male and female UNx db/db mice developed similar hallmarks of DN pathology, suggesting no or weak sex differences in the functional and structural changes during DN progression.

Wenshen Jianpi recipe, a blended traditional Chinese medicine, ameliorates proteinuria and renal injury in a rat model of diabetic nephropathy

Background

Wenshen Jianpi recipe (WSJPR), a blended traditional Chinese medicine, is considered to have the possible beneficial effect on the progression of diabetic nephropathy (DN). This present study was designed to elucidate this protective activity in a rat model with streptozotocin (STZ)-induced DN and to explore the possible underlying mechanism.

Methods

Adult Sprague Dawley (SD) rats were induced to develop DN through intraperitoneal injection of STZ (60 mg/kg). Animals were orally administered saline, WSJPR at 7.5, 15, 30 g/kg, and valsartan (25 mg/kg) daily for 8 weeks. Blood and 24-h urine samples of each rat were collected for biochemical examination at 2-week intervals. Microcirculatory blood flow in the renal cortex and hemorheology index were also measured. At the end of 8 weeks, all rats were sacrificed to obtain the kidney tissues for histological examination and reverse transcription polymerase chain reaction (RT-PCR) was used to analyze the transcriptional levels of nephrin and podocin genes.

Results

WSJPR could improve serum total protein (TP) and albumin (ALB), reduce the excretion rates of urine-TP (U-TP), urine-ALB (U-ALB) and urine urea nitrogen (UUN) (P < 0.05), although it did not significantly alter the hyperglycemia. In addition, treatment with WSJPR could strongly reduce blood flow, erythrocyte aggregation index, and ameliorate microcirculation. In histological measurement, WSJPR-treated rats showed a significant amelioration in glomerular hypertrophy and mesangial expansion. By RT-PCR, we found WSJPR up-regulated the nephrin and podocin expression at mRNA levels.

Conclusion

This study suggested that WSJPR could effectively relieve renal damage and improve renal function of DN rats by ameliorating metabolism disorder and increasing the gene expression of nephrin and podocin, which might be a useful approach for the treatment of DN.

Association of renal arteriosclerosis and hypertension with renal and cardiovascular outcomes in Japanese type 2 diabetes patients with diabetic nephropathy

AIMS/INTRODUCTION

The present retrospective study investigated the impact of renal arteriosclerosis (AS) and hypertension (HT) on long-term renal and cardiovascular outcomes in Japanese type 2 diabetes patients with biopsy-proven diabetic nephropathy.

MATERIALS AND METHODS

A total of 185 patients were enrolled. Patients were divided into four groups stratified by renal AS status and the presence of HT. The outcomes for this study were the first occurrence of renal events (a need for dialysis or a 30% decline in estimated glomerular filtration rate from baseline) and cardiovascular events (cardiovascular death, non-fatal myocardial infarction, coronary intervention or non-fatal stroke).

RESULTS

The proportion of renal AS scores ≥1 was 88.3% among patients with normal-range blood pressure (BP) and 95.4% among patients with HT. During a mean follow-up period of 7.6 years, 129 episodes of renal composite events and 55 episodes of cardiovascular events were observed. Compared with patients with no renal AS and normal-range BP, a renal AS score ≥1 increased the risk of renal composite events with a multivariable-adjusted hazard ratio of 3.21 (95% confidence interval [95% CI] 1.27-8.14) in patients with normal-range BP and 4.99 (95% CI 1.98-12.54) in patients with HT, whereas renal AS score ≥1 increased the risk of cardiovascular events with a multivariable-adjusted hazard ratio of 6.06 (95% CI 1.24-29.61) in patients with normal-range BP and 10.02 (95% CI 1.92-52.39) in patients with HT.

CONCLUSIONS

Renal AS was associated with increasing risks for renal composite events and cardiovascular events in both normal-range BP and HT. The risks of renal composite events and cardiovascular events were the highest in both renal AS and HT.

Personalized medicine in diabetic kidney disease: a novel approach to improve trial design and patient outcomes

PURPOSE OF REVIEW

In the last decade many attempts have been made to reduce the high residual risk of end-stage kidney disease and cardiovascular disease in patients with diabetic kidney disease by targeting a variety of risk markers. Subsequent analyses revealed that the variation in individual drug response to the tested interventions partly explains why these trials did not result in additional kidney or cardiovascular protection. This review summarizes recent insights regarding individual variation in drug response. Additionally, we explore novel approaches to incorporate this drug response variability in the design of new clinical trials.

RECENT FINDINGS

Recent studies suggest that a plausible explanation for individual therapy resistance emanates from intrinsic individual characteristics such as genetic make-up or volume status and is likely only partially explained by drug characteristics such as the dose or type of intervention. Biomarker-based enrichment strategies to identify high-risk individuals and/or those who are more likely to respond to interventions offer opportunities to tailor therapies to individual patients.

SUMMARY

Individual drug response variability is a recognized phenomenon in clinical practice. It is time to implement novel approaches that take into account this response variability in the design of new trials in diabetic kidney disease in order to define optimal therapies for individual patients.

Coreopsis tinctoria Nutt ameliorates high glucose-induced renal fibrosis and inflammation via the TGF-β1/SMADS/AMPK/NF-κB pathways

BACKGROUND

Coreopsis tinctoria Nutt is an ethnomedicine widely used in Xinjiang, China. It is consumed as a herbal tea by local Uyghur people to treat high blood pressure and diarrhea. Our previous study confirmed that the ethyl acetate extract of Coreopsis tinctoria (AC) had a protective effect on diabetic nephropathy (DN) in an in vivo experiment. Here we aim to elucidate the protective mechanism of AC and marein, the main ingredient in Coreopsis tinctoria on renal fibrosis and inflammation in vitro under high glucose (HG) conditions.

METHODS

A HG-induced barrier dysfunction model in rat mesangial cells (HBZY-1) was established. The cells were exposed to AC and marein and/or HG for 24 h. Then, the renal protective effects of AC and marein via transforming growth factor-β1 (TGF-β1)/Smads, AMP-activated kinase protein (AMPK), and nuclear factor kappa beta (NF-κB) signaling were assessed.

RESULTS

Both AC and marein suppressed rat mesangial cell hyperplasia and significantly attenuated the expression of HG-disrupted fibrotic and inflammatory proteins in HBZY-1 cells. It was also confirmed that AC and marein remarkably attenuated HG-induced renal inflammation and fibrosis by regulating the AMPK, TGF-β1/Smads, and NF-κB signaling pathways.

CONCLUSION

These results indicated that AC and marein may delay the progression of DN, at least in part, by suppressing HG-induced renal inflammation and fibrosis. Marein may be one of the bioactive compounds in AC.

Association between E469K polymorphism in the ICAM1 gene and the risk of diabetic nephropathy: a meta-analysis

BACKGROUND

Inflammation may be a key pathophysiological mechanism in diabetic nephropathy (DN). Intercellular adhesion molecule 1 (ICAM1) is an acute phase marker of inflammation. ICAM1 rs5498 has been reported to be associated with the risk of DN. However, the previous findings were conflicting due to the limited sample sizes, different methodologies and ethnicities. Therefore, this study aimed to investigate the genetic association between ICAM1 rs5498 and the risk of DN.

METHODS

Two investigators independently searched the studies from the databases PubMed, Web of Science, the Cochrane Library, Chinese National Knowledge Infrastructure (CNKI) and Embase. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the associations.

RESULTS

No significant association was detected between ICAM1 rs5498 and DN susceptibility in allelic and recessive models (p > 0.05). However, significant reduction of frequencies of the dominant model of ICAM1 rs5498 was only detected in the Caucasian subgroup (OR = 0.80; 95% CI = [0.65, 0.99], p = 0.04) and type 1 diabetes mellitus subgroup (OR = 0.80; 95% CI = [0.65, 0.99], p = 0.04).

CONCLUSIONS

Thus, ICAM1 rs5498 might be a risk factor for DN in Caucasians and type 1 diabetes mellitus patients, which suggested that ICAM1 rs5498 might help in early diagnosis and prevention of this disease. Further studies were needed to clarify the biochemical function and pathological role of ICAM1 rs5498 in the risk of DN.

Amelioration of diabetic nephropathy in db/db mice treated with tibetan medicine formula Siwei Jianghuang Decoction Powder extract

Siwei Jianghuang Decoction Powder (SWJH) documented originally in the Four Medical Tantras-Blue Glaze exhibited beneficial effects on diabetic nephropathy (DN) via combined synergistically action of multiple formula components including Curcumae longae Rhizoma, Berberidis dictyophyllae Cortex, Phyllanthi Fructus and Tribuli Fructus. This study investigated the effects of SWJH on DN in db/db mice and possible underlying mechanisms. The ten weeks old db/db mice treated with SWJH by intra-gastric administration once a day for 8 weeks. After 8 weeks, body weight, water and food intake of mice were recorded. The level of fasting blood glucose (FBG) was measured. Serum creatinine (Scr), blood urea nitrogen (BUN), urine microalbumin (UMAlb), serum uric acid (UA) and urinary albumin excretion (UAE) were detected. An enzyme-linked immunosorbent assay was performed to test serum vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGF-β1). Real-time PCR and Western blot analysis were used to test mRNA and protein expression of hypoxia inducible factor-1α (HIF-1α), VEGF and TGF-β1 in kidney tissue. SWJH treatment significantly reduced the levels of FBG, Scr, BUN, UMAlb, UA and UAE and retarded renal fibrosis. SWJH treatment further significantly reduced serum TGF-β1 level and downregulated the expression of HIF-1α, VEGF and TGF-β1 at both mRNA and protein levels. Principal component analysis and partial least squares regression and hierarchical cluster analysis demonstrated that SWJH treatment significantly ameliorated renal damage in DN mice. These consequences suggested that SWJH formulations were effective in the treatment of DN through regulating the HIF-1α, VEGF and TGF-β1 overexpression.

Endothelin A receptor antagonists in diabetic kidney disease

PURPOSE OF REVIEW

Despite optimal therapy of diabetic nephropathy with agents blocking the renin-angiotensin-aldosterone system, the residual risk of nephropathy progression to end-stage renal disease (ESRD) remains high. The purpose of this review is to discuss the potential role of endothelin antagonism as a therapeutic tool to reduce residual proteinuria and delay kidney injury progression among patients with diabetic nephropathy.

RECENT FINDINGS

Preclinical studies have shown that endothelin receptor antagonists (ERAs) exert proteinuria lowering and nephroprotective actions in experimental models of diabetic nephropathy. ERAs reduce proteinuria in phase 2 trials that included therapy with renin-angiotensin-aldosterone system blockers. Safety of these agents and protection from ESRD needs to be demonstrated in phase 3 trials. Excess risk of fluid retention and heart failure risk remains.

SUMMARY

The hypothesis that the antiproteinuric effect of endothelin antagonism may be translated into a slower progression of diabetic nephropathy to ESRD is investigated in ongoing randomized trials assessing 'hard' renal endpoints. ERAs may represent a promising tool toward renoprotection in diabetic nephropathy by individualizing therapy and mitigating the risk of heart failure, if these trials are positive.

The potential role and rationale for treatment of heart failure with sodium-glucose co-transporter 2 inhibitors

Heart failure (HF) and type 2 diabetes mellitus (T2DM) are both growing public health concerns contributing to major medical and economic burdens to society. T2DM increases the risk of HF, frequently occurs concomitantly with HF, and worsens the prognosis of HF. Several anti-hyperglycaemic medications have been associated with a concern for worse HF outcomes. More recently, the results of the EMPA-REG OUTCOME trial showed that the sodium-glucose co-transporter 2 (SGLT2) inhibitor empagliflozin was associated with a pronounced and precocious 38% reduction in cardiovascular mortality in subjects with T2DM and established cardiovascular disease [Correction added on 8 September 2017, after first online publication: "32%" in the previous sentence was corrected to "38%"]. These benefits were more related to a reduction in incident HF events rather than to ischaemic vascular endpoints. Several mechanisms have been put forward to explain these benefits, which also raise the possibility of using these drugs as therapies not only in the prevention of HF, but also for the treatment of patients with established HF regardless of the presence or absence of diabetes. Several large trials are currently exploring this postulate.

Pleiotropic effects of liraglutide treatment on renal risk factors in type 2 diabetes: Individual effects of treatment

AIMS/HYPOTHESIS

Management of diabetic nephropathy includes reduction of albuminuria, blood pressure and weight. The GLP-1 receptor agonist liraglutide may possess these pleiotropic effects in addition to the glucose lowering effect. We aimed to elucidate the individual liraglutide treatment response by determining if high responders (highest reduction) in each risk factor also had high response in other renal risk factors (cross-dependency).

METHODS

Open-label study: 31 type 2 diabetics treated with liraglutide for 7weeks. After 3weeks washout 23 re-started treatment and were followed for 1year. HbA_1c, weight, systolic blood pressure (SBP), urinary albumin excretion rate (UAER) and mGFR (⁵¹Cr-EDTA) were evaluated. Changes in high (Q4) vs. low responders (Q1-Q3) were compared for each renal risk factor. The effects of treatment/off treatment/re-treatment (off-on/off-on effect) were evaluated to account for random effects.

RESULTS

After 7weeks HbA_1c was reduced 6(95% CI: 3;9)mmol/mol, weight 2.5(1.8;3.2)kg, SBP 4(-1;9)mmHg, UAER 30(12;44)% and mGFR 11(7;14)ml/min per 1.73m². mGFR high responders had a significant reduction in weight compared to low responders (4.3 vs. 1.9kg; p=0.002). SBP high responders had a tendency of a higher reduction in UAER compared to low responders (47 vs. 23%, p=0.14). No cross-dependency was observed in any of the other renal risk factors (p≥0.16). Treatment response did not differ after 7weeks and 1year (p≥0.12).

CONCLUSIONS/INTERPRETATION

Liraglutide possesses pleiotropic effects on renal risk factors. On patient level, effect on the individual risk factor cannot be anticipated based on response in other risk factors. Response when re-starting treatment did not differ, indicating that our primary findings were not random.

Synergistic interaction of effective parts in Rehmanniae Radix and Cornus officinalis ameliorates renal injury in C57BL/KsJ-db/db diabetic mice: Involvement of suppression of AGEs/RAGE/SphK1 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Rehmanniae Radix (RR) and Cornus officinalis (CO) are two traditional Chinese medicines widely used in China for treating diabetes mellitus and its complications, such as diabetic nephropathy. Iridoid glycoside of Cornus officinalis (IGCO), triterpenoid acid of Cornus officinalis (TACO) and iridoid glycoside of Rehmanniae Radix (IGRR) formed an innovative formula named combinatorial bioactive parts (CBP). The aims of the present study were to investigate the renoprotective effects of CBP on DN through the inhibition of AGEs/RAGE/SphK1 signaling pathway activation, and identify the advantage of CBP compared with IGCO, TACO, IGRR.

MATERIALS AND METHODS

The db/db diabetic renal injury model was used to examine the renoprotective effects of CBP, IGCO, TACO and IGRR. For mechanistic studies, diabetic symptoms, renal functions, and pathohistology of pancreas and kidney were evaluated. AGEs/RAGE/SphK1 pathway were determined.

RESULTS

CBP, IGCO, TACO and IGRR inhibited the decrease in serum insulin levels and the increases in urine volume, food consumption, water intake, TC, TG, glycated serum protein, fasting blood glucose levels, 24h urine protein levels, and serum levels of urea nitrogen and creatinine. It also prevented ECM accumulation and improved the histology of pancreas and kidney, and alleviated the structural alterations in mesangial cells and podocytes in renal cortex. Moreover, CBP, IGCO, TACO and IGRR down-regulated the elevated staining, protein levels of RAGE, SphK1, TGF-β and NF-κB. Among the treatment groups, CBP produced the strongest effects.

CONCLUSIONS

These findings suggest that the inhibitory effect of CBP, IGCO, TACO and IGRR on the activation of AGEs/RAGE/SphK1 signaling pathway in db/db diabetic mice kidney is a novel mechanism by which CBP, IGCO, TACO and IGRR exerts renoprotective effects on DN. Among all the groups, CBP produced the strongest effect while IGCO, TACO and IGRR produced weaker effects.

Dapagliflozin reduces albuminuria in patients with diabetes and hypertension receiving renin-angiotensin blockers

AIMS

To characterize the effect of dapagliflozin on albuminuria and estimated glomerular filtration rate (eGFR) and to determine whether effects on albuminuria were mediated through changes in glycated haemoblogin (HbA1c), systolic blood pressure (SBP), body weight or eGFR.

METHODS

We conducted a post hoc analysis of data pooled from two phase III clinical trials in hypertensive patients with type 2 diabetes (T2DM) on stable angiotensin-converting enzyme inhibitor or angiotensin receptor blocker therapy, randomly assigned to dapagliflozin 10 mg/day or matched placebo. This analysis included only patients with microalbuminuria or macroalbuminuria at baseline.

RESULTS

Patients were randomized to receive dapagliflozin 10 mg (n = 167) or placebo (n = 189). Dapagliflozin resulted in greater 12-week reductions in albuminuria compared with placebo: -33.2% [95% confidence interval (CI) -45.4, -18.2]. The reduction in albuminuria was also present after adjusting for age, sex and changes in HbA1c, SBP, body weight and eGFR: -23.5% (95% CI -37.6, -6.3). There was a decrease in eGFR with dapagliflozin versus placebo that was readily reversed 1 week after last dose. No serious renal-related adverse events were observed in any group.

CONCLUSIONS

Dapagliflozin was effective in lowering albuminuria in patients with T2DM and hypertension using renin-angiotensin system blockade therapy. Reductions in albuminuria were still present after adjusting for changes in HbA1c, SBP, body weight and eGFR. Dapagliflozin-induced improvements in glycaemic control and reductions in SBP, coupled with other potentially beneficial renal effects, may lead to a reduced long-term renal and cardiovascular risk.

Prediction of the effect of atrasentan on renal and heart failure outcomes based on short-term changes in multiple risk markers

BACKGROUND

A recent phase II clinical trial (Reducing Residual Albuminuria in Subjects with Diabetes and Nephropathy with AtRasentan trial and an identical trial in Japan (RADAR/JAPAN)) showed that the endothelin A receptor antagonist atrasentan lowers albuminuria, blood pressure, cholesterol, hemoglobin, and increases body weight in patients with type 2 diabetes and nephropathy. We previously developed an algorithm, the Parameter Response Efficacy (PRE) score, which translates short-term drug effects into predictions of long-term effects on clinical outcomes.

DESIGN

We used the PRE score on data from the RADAR/JAPAN study to predict the effect of atrasentan on renal and heart failure outcomes.

METHODS

We performed a post-hoc analysis of the RADAR/JAPAN randomized clinical trials in which 211 patients with type-2 diabetes and nephropathy were randomly assigned to atrasentan 0.75 mg/day, 1.25 mg/day, or placebo. A PRE score was developed in a background set of completed clinical trials using multivariate Cox models. The score was applied to baseline and week-12 risk marker levels of RADAR/JAPAN participants, to predict atrasentan effects on clinical outcomes. Outcomes were defined as doubling serum creatinine or end-stage renal disease and hospitalization for heart failure.

RESULTS

The PRE score predicted renal risk changes of -23% and -30% for atrasentan 0.75 and 1.25 mg/day, respectively. PRE scores also predicted a small non-significant increase in heart failure risk for atrasentan 0.75 and 1.25 mg/day (+2% vs. +7%). Selecting patients with >30% albuminuria reduction from baseline (responders) improved renal outcome to almost 50% risk reduction, whereas non-responders showed no renal benefit.

CONCLUSIONS

Based on the RADAR/JAPAN study, with short-term changes in risk markers, atrasentan is expected to decrease renal risk without increased risk of heart failure. Within this population albuminuria responders appear to contribute to the predicted improvements, whereas non-responders showed no benefit. The ongoing hard outcome trial (SONAR) in type 2 diabetic patients with >30% albuminuria reduction to atrasentan will allow us to assess the validity of these predictions.

Protective effects of Danggui Buxue Tang on renal function, renal glomerular mesangium and heparanase expression in rats with streptozotocin-induced diabetes mellitus

Danggui Buxue Tang (DBT) is a simple combination of Radix Astragali and Radix Angelica sinensis (5:1), with a variety pharmacological activities. In the present study, a single intravenous injection of 30 mg/kg streptozotocin and subsequent six weeks of high glucose diet in Sprague Dawley rats were used to induce diabetic nephropathy. Rats with diabetes mellitus showed increased levels of fasting blood glucose (FBG), blood urea nitrogen (BUN), serum creatinine (Scr), serum and urine β2-microglobulins (β2-MG), and type IV collagen (all P<0.05). DBT treatment significantly decreased the levels of FBG, BUN, Scr, serum and urine β2-MG, and type IV collagen. Furthermore, DBT treatment significantly and dose-dependently restored the ultrastructural injury, and reduced the expression of heparanase, compared with the vehicle (P<0.05). Therefore, DBT may be a novel therapeutic approach for the prevention and treatment of diabetic nephrology.

Renal end points in clinical trials of kidney disease

PURPOSE OF REVIEW

End-stage renal disease and doubling of serum creatinine are established hard end points in clinical trials of chronic kidney disease (CKD). These end points are debated, as their accuracy and precision may not be optimal, and as they are late events in the progression of CKD, thereby requiring large and complex trials. The purpose of this review is to examine the validity of the currently used established renal end point by comparing the end-stage renal disease part, involving renal replacement therapies (RRTs) (dialysis or renal transplantation), and the glomerular filtration-based end points involving the doubling of serum creatinine.

RECENT FINDINGS

Emerging data demonstrate that the RRT decision depends not only on serum creatinine but also on a range of subjective factors involving a patient's well-being, availability of RRTs, or local guidelines. Thus, initiation of RRT is not representative of (estimated) glomerular filtration rate [(e)GFR] decline alone. In contrast, a doubling of serum creatinine reflects a sustained loss in a patient's starting GFR. The disadvantage of an end point based on a filtration marker is that many drugs exert opposite effects on the GFR. Initially, they cause a reduction in GFR followed by a stabilization of GFR decline. This ambiguous pattern complicates the interpretation of the drug effect, in particular when the end point is based on lesser declines in GFR, such as a 30% or 40% decline.

SUMMARY

The currently used end points in CKD trials reflect different functions of the kidney. In the future, we have to establish whether we want to characterize the effect of a novel drug on a renal filtration marker alone, on a combination of parameters involving a patient's well-being, or on a composite of these.

MicroRNA biomarkers in clinical renal disease: from diabetic nephropathy renal transplantation and beyond

Chronic Kidney Disease (CKD) is a common health problem affecting 1 in 12 Americans. It is associated with elevated risks of mortality, cardiovascular disease, and high costs for the treatment of renal failure with dialysis or transplantation. Advances in CKD care are impeded by the lack of biomarkers for early diagnosis, assessment of the extent of tissue injury, estimation of disease progression, and evaluation of response to therapy. Such biomarkers should improve the performance of existing measures of renal functional impairment (estimated glomerular filtration rate, eGFR) or kidney damage (proteinuria). MicroRNAs (miRNAs) a class of small, non-coding RNAs that act as post-transcriptional repressors are gaining momentum as biomarkers in a number of disease areas. In this review, we examine the potential utility of miRNAs as promising biomarkers for renal disease. We explore the performance of miRNAs as biomarkers in two clinically important forms of CKD, diabetes and the nephropathy developing in kidney transplant recipients. Finally, we highlight the pitfalls and opportunities of miRNAs and provide a broad perspective for the future clinical development of miRNAs as biomarkers in CKD beyond the current gold standards of eGFR and albuminuria.

Liuwei Dihuang Pills Enhance the Effect of Western Medicine in Treating Diabetic Nephropathy: A Meta-Analysis of Randomized Controlled Trials

Objectives. To assess the effectiveness and adverse effects of adding Liuwei Dihuang Pills (LDP) to Western medicine for treating diabetic nephropathy. Methods. Studies were retrieved from seven electronic databases, including PubMed, Embase, The Cochrane Library, CBM, CNKI, Chinese Scientific Journal Database (VIP), and Wanfang Data until November 2015. Study selection, data extraction, quality assessment, and data analyses were conducted according to Cochrane standards. Meta-analysis was performed on the overall therapeutic efficacy of hyperglycemia and renal functions, and the study also analyzed adverse events. Results. A total of 1,275 patients from 18 studies were included. The methodological quality of these included trials was generally low. We found that adding LDP can lower patients' FBG (MD: −0.36 [−0.46, −0.25], P < 0.00001), PBG (MD: −1.10 [−1.35, −0.85], P < 0.00001), and HbA1c (MD: −0.14 [−0.49, 0.21], P = 0.43). There were also improvements in lowering patients' BUN (MD: −0.67 [−0.89, −0.45], P < 0.00001), SCr (MD: −0.96 [−1.53, −0.39], P < 0.00001), 24 h UTP (SMD: −1.26 [−2.38, −0.15], P < 0.00001), UAER (MD: −26.18 [−27.51, −24.85], P < 0.00001), and UmAlb (SMD: −1.72 [−2.67, −0.77], P < 0.00001). Conclusion. There is encouraging evidence that adding LDP to Western medicine might improve treatment outcomes of diabetic nephropathy, including hyperglycemia and renal functions. However, the evidence remains weak. More rigorous high-quality trials are warranted to substantiate or refute the results.

Evaluation of biochemical and clinical markers of endothelial dysfunction and their correlation with urinary albumin excretion in patients with type 1 diabetes mellitus

Objective Endothelial dysfunction (ED) plays an important role in the pathogenesis of diabetic nephropathy. The purpose of the study was to determine flow mediated endothelial dependent vasodilatation (FMD) measurements and serum soluble (s) endothelin-1 (ET-1), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM-1) levels in patients with type 1 diabetes mellitus (T1DM) with or without increased urinary albumin excretion (UAE) and compare them with the healthy controls. Subjects and methods Seventy three patients with T1DM were enrolled. Patients were divided into two subgroups according to microalbumin measurements in 24-hr urine collections. The diabetic patients without microalbuminuria (41 patients) were defined as Group I and those with microalbuminuria (32 patients) were defined as group II. A hundred age and sex matched healthy subjects participated as the control group (Group III). Serum sET-1, sICAM-1, sVCAM-1 levels and FMD measurements were determined in all participants. Results Median FMD measurement was significantly lower in the diabetic groups compared with the control group (6.6, 6.4 and 7.8% in Group I, II and III, respectively) (p < 0.05). FMD was negatively correlated with age (p = 0.042). Median serum sICAM-1 level was higher in the patient groups compared to the control group (p < 0.05). Median serum sVCAM-1 level was higher in the group of patients with increased albuminuria compared to the normoalbuinuric and the control group (p < 0.05). Serum sVCAM-1 level was found to be positively correlated with degree of urinary albumin excretion (p < 0.001). Conclusion We assume that sVCAM-1 may be used as a predictive marker for risk stratification for nephropathy development and progression.

Review of Herbal Traditional Chinese Medicine for the Treatment of Diabetic Nephropathy

Diabetic nephropathy (DN) is the most serious chronic complications of diabetes; 20-40% of diabetic patients develop into end stage renal disease (ESRD). However, exact pathogenesis of DN is not fully clear and we have great difficulties in curing DN; poor treatment of DN led to high chances of mortality worldwide. A lot of western medicines such as ACEI and ARB have been demonstrated to protect renal function of DN but are not enough to delay or retard the progression of DN; therefore, exploring exact and feasible drug is current research hotspot in medicine. Traditional Chinese medicine (TCM) has been widely used to treat and control diabetes and its complications such as DN in a lot of scientific researches, which will give insights into the mechanism of DN, but they are not enough to reveal all the details. In this paper, we summarize the applications of herbal TCM preparations, single herbal TCM, and/or monomers from herbal TCM in the treatment of DN in the recent 10 years, depicting the renal protective effects and the corresponding mechanism, through which we shed light on the renal protective roles of TCM in DN with a particular focus on the molecular basis of the effect and provide a beneficial supplement to the drug therapy for DN.

Protective effect of thymol on high fat diet induced diabetic nephropathy in C57BL/6J mice

Obesity is one of several factors implicated in chronic kidney disease (CKD). Thymol, a monoterpene phenolic compound found in the oils of thyme with multiple biological properties especially antidiabetic activity. The present study was undertaken to evaluate the thymol against diabetic nephropathy by high fat diet (HFD)-induced diabetic C57BL/6J mice. After 10 weeks of continuous dietary intervention, HFD (fat- 35.2%) to mice presented characteristic features of progressive nephropathy by significant increased in kidney weight, blood, and urinary parameters, glomerulosclerosis, oxidative stress, hyperlipidemia and subsequent renal injuries. After intragastric administration of thymol (40 mg/kg BW) daily for the subsequent 5 weeks significantly decreased the blood, urinary parameters and kidney weight. Thymol inhibited the activation of transforming growth factor-β1 (TGF-β1) and vascular endothelial growth factor (VEGF). Also, significantly increased the antioxidants and suppresses the lipid peroxidation markers in erythrocytes and kidney tissue compared to the diabetic mice. Thymol downregulated the expression level of sterol regulatory element binding protein-1c (SREBP-1c) and reduced the lipid accumulation in renal. Histopathological study of kidney tissues showed that extracellular mesangial matrix expansion, glomerulosclerosis in diabetic mice were suppressed by thymol. Further, our results indicate that administration of thymol afforded remarkable protection against HFD-induced diabetic nephropathy.

The effect of CCR2 inhibitor CCX140-B on residual albuminuria in patients with type 2 diabetes and nephropathy: a randomised trial

BACKGROUND

Patients with type 2 diabetes and nephropathy have high cardiorenal morbidity and mortality despite optimum treatment including angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs). Residual risk is related to residual albuminuria. We assessed whether CCX140-B, a selective inhibitor of C-C chemokine receptor type 2 (CCR2), could further reduce albuminuria when given in addition to standard care, including ACE inhibitors or ARBs.

METHODS

In this randomised, double-blind, placebo-controlled clinical trial, we recruited patients from 78 research centres in Belgium, Czech Republic, Germany, Hungary, Poland, and the UK. We enrolled patients with type 2 diabetes aged 18-75 years with proteinuria (first morning void urinary albumin to creatinine ratio [UACR] 100-3000 mg/g), estimated glomerular filtration rate of 25 mL/min per 1·73 m(2) or higher, and taking stable antidiabetic treatment and ACE inhibitors or ARBs, for at least 8 weeks before study entry. Patients were stratified based on baseline UACR and renal function (estimated glomerular filtration rate), and then randomly assigned (1:1:1) via an interactive web response system with a minimisation algorithm to oral placebo, 5 mg CCX140-B, or 10 mg CCX140-B once a day. The 12-week dosing period in the initial protocol was extended to 52 weeks by protocol amendment. The primary efficacy measure was change from baseline in UACR during 52 weeks in the modified intention-to-treat population (all patients with uninterrupted dosing, excluding patients who stopped dosing at week 12 either permanently under the original protocol, or temporarily because of delay in approval of the protocol amendment). We did safety analyses on all randomly assigned patients who received at least one dose of study drug. According to a prespecified analysis plan, we analysed the primary endpoint with one-sided statistical testing with calculation of upper 95% confidence limits of the differences between active and control. This trial is registered with ClinicalTrials.gov, number NCT01447147.

FINDINGS

The study ran from Dec 7, 2011 (first patient enrolled), until Aug 4, 2014. We enrolled 332 patients: 111 were assigned to receive placebo, 110 to 5 mg CCX140-B, and 111 to 10 mg CCX140-B. Of these, 192 were included in the modified intention-to-treat population. UACR changes from baseline during 52 weeks were -2% for placebo (95% CI -11% to 9%), -18% for 5 mg CCX140-B (-26% to -8%), and -11% for 10 mg CCX140-B (-20% to -1%). We recorded a -16% difference between 5 mg CCX140-B and placebo (one-sided upper 95% confidence limit -5%; p=0·01) and a -10% difference between 10 mg CCX140-B and placebo (upper 95% confidence limit 2%; p=0·08). Adverse events occurred in 81 (73%) of 111 patients in the placebo group versus 71 (65%) of 110 patients in the CCX140-B 5 mg group and 68 (61%) of 111 patients in the CCX140-B 10 mg group; there were no renal events during the study.

INTERPRETATION

Our data suggest that CCR2 inhibition with CCX140-B has renoprotective effects on top of current standard of care in patients with type 2 diabetes and nephropathy.

FUNDING

ChemoCentryx.

Additive protection by LDR and FGF21 treatment against diabetic nephropathy in type 2 diabetes model

The onset of diabetic nephropathy (DN) is associated with both systemic and renal changes. Fibroblast growth factor (FGF)-21 prevents diabetic complications mainly by improving systemic metabolism. In addition, low-dose radiation (LDR) protects mice from DN directly by preventing renal oxidative stress and inflammation. In the present study, we tried to define whether the combination of FGF21 and LDR could further prevent DN by blocking its systemic and renal pathogeneses. To this end, type 2 diabetes was induced by feeding a high-fat diet for 12 wk followed by a single dose injection of streptozotocin. Diabetic mice were exposed to 50 mGy LDR every other day for 4 wk with and without 1.5 mg/kg FGF21 daily for 8 wk. The changes in systemic parameters, including blood glucose levels, lipid profiles, and insulin resistance, as well as renal pathology, were examined. Diabetic mice exhibited renal dysfunction and pathological abnormalities, all of which were prevented significantly by LDR and/or FGF21; the best effects were observed in the group that received the combination treatment. Our studies revealed that the additive renal protection conferred by the combined treatment against diabetes-induced renal fibrosis, inflammation, and oxidative damage was associated with the systemic improvement of hyperglycemia, hyperlipidemia, and insulin resistance. These results suggest that the combination treatment with LDR and FGF21 prevented DN more efficiently than did either treatment alone. The mechanism behind these protective effects could be attributed to the suppression of both systemic and renal pathways.

The renal protective effect of angiotensin receptor blockers depends on intra-individual response variation in multiple risk markers

AIMS

Angiotensin receptor blockers (ARBs) are renoprotective and targeted to blood pressure. However, ARBs have multiple other (off-target) effects which may affect renal outcome. It is unknown whether on-target and off-target effects are congruent within individuals. If not, this variation in short term effects may have important implications for the prediction of individual long term renal outcomes. Our aim was to assess intra-individual variability in multiple parameters in response to ARBs in type 2 diabetes.

METHODS

Changes in systolic blood pressure (SBP), albuminuria, potassium, haemoglobin, cholesterol and uric acid after 6 months of losartan treatment were assessed in the RENAAL database. Improvement in predictive performance of renal outcomes (ESRD or doubling serum creatinine) for each individual using ARB-induced changes in all risk markers was assessed by the relative integrative discrimination index (RIDI).

RESULTS

SBP response showed high variability (mean -5.7 mmHg, 5(th) to 95(th) percentile -36.5 to +24.0 mmHg) between individuals. Changes in off-target parameters also showed high variability between individuals. No congruency was observed between responses to losartan in multiple parameters within individuals. Using individual responses in all risk markers significantly improved renal risk prediction (RIDI 30.4%, P < 0.01) compared with using only SBP changes. Results were successfully replicated in two independent trials with irbesartan, IDNT and IRMA-2.

CONCLUSIONS

In this post hoc analysis we showed that ARBs have multiple off-target effects which vary between and within individuals. Combining all ARB-induced responses beyond SBP provides a more accurate prediction of who will benefit from ARB therapy. Prospective trials are required to validate these findings.

Pleiotropic effects of type 2 diabetes management strategies on renal risk factors

In parallel with the type 2 diabetes pandemic, diabetic kidney disease has become the leading cause of end-stage renal disease worldwide, and is associated with high cardiovascular morbidity and mortality. As established in landmark randomised trials and recommended in clinical guidelines, prevention and treatment of diabetic kidney disease focuses on control of the two main renal risk factors, hyperglycaemia and systemic hypertension. Treatment of systemic hypertension with angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers is advocated because these drugs seem to exert specific renoprotective effects beyond blood pressure lowering. Emerging evidence shows that obesity, glomerular hyperfiltration, albuminuria, and dyslipidaemia might also adversely affect the kidney in diabetes. Control of these risk factors could have additional benefits on renal outcome in patients with type 2 diabetes. However, despite multifactorial treatment approaches, residual risk for the development and progression of diabetic kidney disease in patients with type 2 diabetes remains, and novel strategies or therapies to treat the disease are urgently needed. Several drugs used in the treatment of type 2 diabetes are associated with pleiotropic effects that could favourably or unfavourably change patients' renal risk profile. We review the risk factors and treatment of diabetic kidney disease, and describe the pleiotropic effects of widely used drugs in type 2 diabetes management on renal outcomes, with special emphasis on antihyperglycaemic drugs.

Combination of active components of Xiexin decoction ameliorates renal fibrosis through the inhibition of NF-κB and TGF-β1/Smad pathways in db/db diabetic mice

Xiexin decoction, a herbal therapeutic agent commonly used in traditional Chinese medicine, is recognized for its beneficial effects on diabetic nephropathy exerted through the combined action of multiple components, including Rhizoma Coptidis alkaloids (A), Radix et Rhizoma Rhei polysaccharides (P), and Radix Scutellaria flavones (F). Our previous studies have shown that a combination of A, P, and F (APF) exhibits renoprotective effects against diabetic nephropathy. This study was aimed at determining the effects of APF on renal fibrosis in diabetic nephropathy and elucidating the underlying molecular mechanisms. To evaluate the effects of APF, in vivo, db/db diabetic mice were orally administered a low or high dose of APF (300 or 600 mg/kg, respectively) once a day for 8 weeks. We evaluated the blood and urine indices of metabolic and renal function, renal tissue histopathology, renal inflammation, and fibrosis. APF treatment significantly ameliorated glucose and lipid metabolism dysfunction, decreased urinary albumin excretion, normalized creatinine clearance, and reduced the morphological changes in renal tissue. Additionally, APF administration in db/db diabetic mice reduced the elevated levels of renal inflammation mediators such as intercellular adhesion molecule-1, monocyte chemotactic protein-1, tumor necrosis factor-α, interleukin-1β, and active nuclear factor κB (NF-κB). APF treatment also reduced type I and IV collagen, transforming growth factor-β1 (TGF-β1), and TGF-β1 type II receptor expression levels, and decreased the phosphorylation of Smad2/3 in the kidneys of db/db diabetic mice. These results suggest that APF reduces renal fibrosis in diabetic nephropathy through the NF-κB and TGF-β1/Smad signaling pathways. In vitro, APF treatment reduced cell proliferation and protein expression of α-smooth muscle actin, collagen I, TGF-β1 and NF-κB in mesangial cells cultured with high glucose concentrations. Our findings indicate that treatment with multi-component herbal therapeutic formulations may be a useful approach for the treatment of diabetic nephropathy.

Effects of combinations of Xiexin decoction constituents on diabetic nephropathy in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Xiexin decoction (XXD) has been used as a treatment for diabetes mellitus for more than 1300 years. XXD constituents with protective effects against diabetic nephropathy (DN) include Rhizoma Coptidis alkaloids (RA), Radix et Rhizoma Rhei polysaccharides (RP), and Radix Scutellaria flavones (RF). The aim of the study is to investigate the effects of combinations of RA, RP, and RF on DN and their mechanisms of action.

MATERIALS AND METHODS

In vitro, high glucose-induced rat mesangial cells were treated with RA, RP, RF, and combinations thereof. Cell proliferation and levels of inflammatory factors were measured. In vivo, high-fat diet and streptozotocin-induced diabetic rats were treated with different combinations of RA, RP, and RF once per day for 12 weeks. Blood and urine biochemical parameters, renal tissue morphology, and inflammation were investigated.

RESULTS

In vitro, the combination of the three groups of components inhibited mesangial cell proliferation and reduced the levels of monocyte chemotactic protein-1 (MCP-1) and collagen IV. The effects of the three constituent groups in combination were stronger than those of each group alone or combinations of two groups. In diabetic rats, combinations of the three groups of herb components ameliorated blood glucose, urinary albumin excretion and decreased renal mesangial matrix expansion and basement membrane thickening. In addition, the combinations reduced renal tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) protein levels, down-regulated the expression of nuclear factor κB (NF-κB) and transforming growth factor beta 1 (TGF-β1), and up-regulated the expression of inhibitor of nuclear factor κB (IκB) protein. Among the three groups of herb components, RA produced the strongest effects, followed by RP, and then by RF.

CONCLUSIONS

The combination of the three groups of herb components produced anti-DN effects through inhibition of inflammation mediated by NF-κB. Among the three groups of herb components, RA produced the strongest effect while RP and RF produced weaker effects.

Baseline characteristics in the Bardoxolone methyl EvAluation in patients with Chronic kidney disease and type 2 diabetes mellitus: the Occurrence of renal eveNts (BEACON) trial

BACKGROUND

Type 2 diabetes mellitus (T2DM) is the most important contributing cause of end-stage renal disease (ESRD) worldwide. Bardoxolone methyl, a nuclear factor-erythroid-2-related factor 2 activator, augments estimated glomerular filtration. The Bardoxolone methyl EvAluation in patients with Chronic kidney disease and type 2 diabetes mellitus: the Occurrence of renal eveNts (BEACON) trial was designed to establish whether bardoxolone methyl slows or prevents progression to ESRD. Herein, we describe baseline characteristics of the BEACON population.

METHODS

BEACON is a randomized double-blind placebo-controlled clinical trial in 2185 patients with T2DM and chronic kidney disease stage 4 (eGFR between 15 and 30 mL/min/1.73 m(2)) designed to test the hypothesis that bardoxolone methyl added to guideline-recommended treatment including inhibitors of the renin-angiotensin-aldosterone system slows or prevents progression to ESRD or cardiovascular death compared with placebo.

RESULTS

Baseline characteristics (mean or percentage) of the population include age 68.5 years, female 43%, Caucasian 78%, eGFR 22.5 mL/min/1.73 m(2) and systolic/diastolic blood pressure 140/70 mmHg. The median urinary albumin:creatinine ratio was 320 mg/g and the frequency of micro- and macroalbuminuria was 30 and 51%, respectively. Anemia, abnormalities in markers of bone metabolism and elevations in cardiovascular biomarkers were frequently observed. A history of cardiovascular disease was present in 56%, neuropathy in 47% and retinopathy in 41% of patients.

CONCLUSIONS

The BEACON trial enrolled a population heretofore unstudied in an international randomized controlled trial. Enrolled patients suffered with numerous co-morbid conditions and exhibited multiple laboratory abnormalities, highlighting the critical need for new therapies to optimize management of these conditions.

Beneficial effects of phlorizin on diabetic nephropathy in diabetic db/db mice

AIMS

This study observes the effects of phlorizin on diabetic nephrology in db/db diabetic mice and explores possible underlying mechanisms.

METHODS

Sixteen diabetic db/db mice and eight age-matched db/m mice were divided into three groups: vehicle-treated diabetic group (DM group), diabetic group treated with phlorizin (DMT group) and normal control group (CC group). Phlorizin was given in normal saline solution by intragastric administration for 10 weeks. Differentially expressed proteins in three groups were identified using iTRAQ quantitative proteomics and the data were further analyzed with ingenuity pathway analysis.

RESULTS

The body weight and serum concentrations of fasting blood glucose (FBG), advanced glycation end products (AGEs), total cholesterol, triglycerides, blood urea nitrogen, creatinine and 24-h urine albumin were increased in the DM group compared to those of the CC group (P<0.05), and they were decreased by treatment with phlorizin (P<0.05). Morphologic observations showed phlorizin markedly attenuated renal injury. Phlorizin prevented diabetic nephropathy by regulating the expression of a series of proteins involved in renal and urological disease, molecular transport, free radical scavenging, and lipid metabolism.

CONCLUSIONS

Phlorizin protects mice from diabetic nephrology and thus may be a novel therapeutic approach for the treatment of diabetic nephrology.

The endothelin antagonist atrasentan lowers residual albuminuria in patients with type 2 diabetic nephropathy

Despite optimal treatment, including renin-angiotensin system (RAS) inhibitors, patients with type 2 diabetic nephropathy have high cardiorenal morbidity and mortality related to residual albuminuria. We evaluated whether or not atrasentan, a selective endothelin A receptor antagonist, further reduces albuminuria when administered concomitantly with maximum tolerated labeled doses of RAS inhibitors. We enrolled 211 patients with type 2 diabetes, urine albumin/creatinine ratios of 300-3500 mg/g, and eGFRs of 30-75 ml/min per 1.73 m(2) in two identically designed, parallel, multinational, double-blind studies. Participants were randomized to placebo (n=50) or to 0.75 mg/d (n=78) or 1.25 mg/d (n=83) atrasentan for 12 weeks. Compared with placebo, 0.75 mg and 1.25 mg atrasentan reduced urine albumin/creatinine ratios by an average of 35% and 38% (95% confidence intervals of 24 to 45 and 28 to 47, respectively) and reduced albuminuria≥30% in 51% and 55% of participants, respectively. eGFR and office BP measurements did not change, whereas 24-hour systolic and diastolic BP, LDL cholesterol, and triglyceride levels decreased significantly in both treatment groups. Use of atrasentan was associated with a significant increase in weight and a reduction in hemoglobin, but rates of peripheral edema, heart failure, or other side effects did not differ between groups. However, more patients treated with 1.25 mg/d atrasentan discontinued due to adverse events. After stopping atrasentan for 30 days, measured parameters returned to pretreatment levels. In conclusion, atrasentan reduced albuminuria and improved BP and lipid spectrum with manageable fluid overload-related adverse events in patients with type 2 diabetic nephropathy receiving RAS inhibitors.

Multiple low-dose radiation prevents type 2 diabetes-induced renal damage through attenuation of dyslipidemia and insulin resistance and subsequent renal inflammation and oxidative stress

BACKGROUND

Dyslipidemia and lipotoxicity-induced insulin resistance, inflammation and oxidative stress are the key pathogeneses of renal damage in type 2 diabetes. Increasing evidence shows that whole-body low dose radiation (LDR) plays a critical role in attenuating insulin resistance, inflammation and oxidative stress.

OBJECTIVE

The aims of the present study were to investigate whether LDR can prevent type 2 diabetes-induced renal damage and the underlying mechanisms.

METHODS

Mice were fed with a high-fat diet (HFD, 40% of calories from fat) for 12 weeks to induce obesity followed by a single intraperitoneal injection of streptozotocin (STZ, 50 mg/kg) to develop a type 2 diabetic mouse model. The mice were exposed to LDR at different doses (25, 50 and 75 mGy) for 4 or 8 weeks along with HFD treatment. At each time-point, the kidney weight, renal function, blood glucose level and insulin resistance were examined. The pathological changes, renal lipid profiles, inflammation, oxidative stress and fibrosis were also measured.

RESULTS

HFD/STZ-induced type 2 diabetic mice exhibited severe pathological changes in the kidney and renal dysfunction. Exposure of the mice to LDR for 4 weeks, especially at 50 and 75 mGy, significantly improved lipid profiles, insulin sensitivity and protein kinase B activation, meanwhile, attenuated inflammation and oxidative stress in the diabetic kidney. The LDR-induced anti-oxidative effect was associated with up-regulation of renal nuclear factor E2-related factor-2 (Nrf-2) expression and function. However, the above beneficial effects were weakened once LDR treatment was extended to 8 weeks.

CONCLUSION

These results suggest that LDR exposure significantly prevented type 2 diabetes-induced kidney injury characterized by renal dysfunction and pathological changes. The protective mechanisms of LDR are complicated but may be mainly attributed to the attenuation of dyslipidemia and the subsequent lipotoxicity-induced insulin resistance, inflammation and oxidative stress.

Clinical challenges in diagnosis and management of diabetic kidney disease

Diabetic kidney disease (DKD) is a major and increasing worldwide public health issue. There is a great need for implementing treatments that either prevent or significantly slow the progression of DKD. Although there have been significant improvements in management, the increasing numbers of patients with DKD illustrate that current management is not wholly adequate. The reasons for suboptimal management include the lack of early diagnosis, lack of aggressive interventions, and lack of understanding about which interventions are most successful. There are a number of challenges and controversies regarding the current management of patients with DKD. Understanding of these issues is needed in order to provide the best care to patients with DKD. This article describes some of the clinically important challenges associated with DKD: the current epidemiology and cost burden and the role of biopsy in the diagnosis of DKD. Treatment controversies regarding current pharmacologic and nonpharmacologic approaches are reviewed and recommendations based on the published literature are made.

Linking the beneficial effects of current therapeutic approaches in diabetes to the vascular endothelin system

The rising epidemic of diabetes worldwide is of significant concern. Although the ultimate objective is to prevent the development and find a cure for the disease, prevention and treatment of diabetic complications is very important. Vascular complications in diabetes, or diabetic vasculopathy, include macro- and microvascular dysfunction and represent the principal cause of morbidity and mortality in diabetic patients. Endothelial dysfunction plays a pivotal role in the development and progression of diabetic vasculopathy. Endothelin-1 (ET-1), an endothelial cell-derived peptide, is a potent vasoconstrictor with mitogenic, pro-oxidative and pro-inflammatory properties that are particularly relevant to the pathophysiology of diabetic vasculopathy. Overproduction of ET-1 is reported in patients and animal models of diabetes and the functional effects of ET-1 and its receptors are also greatly altered in diabetic conditions. The current therapeutic approaches in diabetes include glucose lowering, sensitization to insulin, reduction of fatty acids and vasculoprotective therapies. However, whether and how these therapeutic approaches affect the ET-1 system remain poorly understood. Accordingly, in the present review, we will focus on experimental and clinical evidence that indicates a role for ET-1 in diabetic vasculopathy and on the effects of current therapeutic approaches in diabetes on the vascular ET-1 system.

Bardoxolone methyl in type 2 diabetes and stage 4 chronic kidney disease

BACKGROUND

Although inhibitors of the renin-angiotensin-aldosterone system can slow the progression of diabetic kidney disease, the residual risk is high. Whether nuclear 1 factor (erythroid-derived 2)-related factor 2 activators further reduce this risk is unknown.

METHODS

We randomly assigned 2185 patients with type 2 diabetes mellitus and stage 4 chronic kidney disease (estimated glomerular filtration rate [GFR], 15 to <30 ml per minute per 1.73 m(2) of body-surface area) to bardoxolone methyl, at a daily dose of 20 mg, or placebo. The primary composite outcome was end-stage renal disease (ESRD) or death from cardiovascular causes.

RESULTS

The sponsor and the steering committee terminated the trial on the recommendation of the independent data and safety monitoring committee; the median follow-up was 9 months. A total of 69 of 1088 patients (6%) randomly assigned to bardoxolone methyl and 69 of 1097 (6%) randomly assigned to placebo had a primary composite outcome (hazard ratio in the bardoxolone methyl group vs. the placebo group, 0.98; 95% confidence interval [CI], 0.70 to 1.37; P=0.92). In the bardoxolone methyl group, ESRD developed in 43 patients, and 27 patients died from cardiovascular causes; in the placebo group, ESRD developed in 51 patients, and 19 patients died from cardiovascular causes. A total of 96 patients in the bardoxolone methyl group were hospitalized for heart failure or died from heart failure, as compared with 55 in the placebo group (hazard ratio, 1.83; 95% CI, 1.32 to 2.55; P<0.001). Estimated GFR, blood pressure, and the urinary albumin-to-creatinine ratio increased significantly and body weight decreased significantly in the bardoxolone methyl group, as compared with the placebo group.

CONCLUSIONS

Among patients with type 2 diabetes mellitus and stage 4 chronic kidney disease, bardoxolone methyl did not reduce the risk of ESRD or death from cardiovascular causes. A higher rate of cardiovascular events with bardoxolone methyl than with placebo prompted termination of the trial. (Funded by Reata Pharmaceuticals; BEACON ClinicalTrials.gov number, NCT01351675.).

The gut-renal axis: do incretin-based agents confer renoprotection in diabetes?

Diabetic nephropathy is the leading cause of end-stage renal disease worldwide, and is associated with a high risk of cardiovascular morbidity and mortality. Intensive control of glucose levels and blood pressure is currently the mainstay of both prevention and treatment of diabetic nephropathy. However, this strategy cannot fully prevent the development and progression of diabetic nephropathy, and an unmet need remains for additional novel therapies. The incretin-based agents--agonists of glucagon-like peptide 1 receptor (GLP-1R) and inhibitors of dipeptidyl peptidase 4 (DPP-4), an enzyme that degrades glucagon-like peptide 1--are novel blood-glucose-lowering drugs used in the treatment of type 2 diabetes mellitus (T2DM). Therapeutic agents from these two drug classes improve pancreatic islet function and induce extrapancreatic effects that ameliorate various phenotypic defects of T2DM that are beyond glucose control. Agonists of GLP-1R and inhibitors of DPP-4 reduce blood pressure, dyslipidaemia and inflammation, although only GLP-1R agonists decrease body weight. Both types of incretin-based agents inhibit renal tubular sodium reabsorption and decrease glomerular pressure as well as albuminuria in rodents and humans. In rodents, incretin-based therapies also prevent onset of the morphological abnormalities of diabetic nephropathy.

Effects of dual blockade of the renin-angiotensin system on renal and cardiovascular outcomes in type 2 diabetes with overt nephropathy and hypertension in the ORIENT: a post-hoc analysis (ORIENT-Hypertension)

Combination therapy with angiotensin II receptor blockers and angiotensin-converting enzyme inhibitors (ACEIs) requires further evaluation in patients with diabetic nephropathy and hypertension. In a post hoc analysis of the Olmesartan Reducing Incidence of Endstage renal disease in diabetic Nephropathy Trial with hypertension, we examined the effects of olmesartan on renal and cardiovascular outcomes in the presence or absence of an ACEI. Among 563 patients randomized to receive either olmesartan (n = 280) or placebo (n = 283), 73.5% (n = 414) received a concomitant ACEI. Compared with placebo, olmesartan significantly reduced proteinuria in both the ACEI-treated and non-ACEI-treated groups. The respective changes in the urinary protein creatinine ratio in the olmesartan-treated and placebo-treated groups were -32.6% and +21.1% without an ACEI (P = 0.001) and -17.0% and +2.2% with an ACEI (P = 0.028). In the olmesartan group, 115 patients developed primary renal outcomes (41.1%) compared with 129 (45.6%) in the placebo group (hazard ratio (HR): 0.97, P = 0.787). The respective HRs in the ACEI-treated and non-ACEI-treated groups were 1.02 (P = 0.891) and 0.84 (P = 0.450). 40 olmesartan-treated patients (14.3%) and 53 placebo-treated patients (18.7%) developed secondary cardiovascular outcomes (HR: 0.65, P = 0.042). The respective HRs in the ACEI-treated and non-ACEI-treated groups were 0.69 (P = 0.129) and 0.51 (P = 0.129). Olmesartan was well tolerated. Dual blockade treatment caused more hyperkalemia than monotherapy. In patients with diabetic nephropathy and hypertension, olmesartan significantly reduced proteinuria, independent of ACEI treatment and cardiovascular outcome but failed to show additional renal benefit compared with ACEI treatment alone. The cardiovascular benefit of dual treatment requires further evaluation.

AQP4 KO exacerbating renal dysfunction is mediated by endoplasmic reticulum stress and p66Shc and is attenuated by apocynin and endothelin antagonist CPU0213

Aquaporin 4 (AQP4) is essential in normal kidney. We hypothesized that AQP4 knockout (KO) may exacerbate pro-inflammatory factors in the stress induced renal insufficiency. Mechanisms underlying are likely due to activating renal oxidative stress adaptor p66Shc and endoplasmic reticulum (ER) stress that could be mediated by endothelin (ET)-NADPH oxidase (NOX) pathway. AQP4 KO and wild type (WT) mice were randomly divided into 4 groups: control, isoproterenol (1mg/kg, s.c., 5d), and interventions in the last 3 days with either apocynin (NADPH oxidase inhibitor, 100mg/kg, p.o.) or CPU0213 (a dual endothelin receptor antagonist 200mg/kg, p.o.). In addition, HK2 cells were cultured in 4 groups: control, isoproterenol (10(-6)M), intervened with apocynin (10(-6)M) or CPU0213 (10(-6)M). In AQP4 KO mice elevated creatinine levels were further increased by isoproterenol compared to AQP4 KO alone. In RT-PCR, western blot and immunohistochemical assay p66Shc and PERK were significantly increased in the kidney of AQP4 KO mice, associated with pro-inflammatory factors CX40, CX43, MMP-9 and ETA compared to the WT mice. Expression of AQP4 was escalated in isoproterenol incubated HK2 cells, and the enhanced protein of PERK and p-PERK/PERK, and p66shc in vivo and in vitro were significantly attenuated by either apocynin or CPU0213. In conclusion, AQP4 KO deteriorates renal dysfunction due to exacerbating ER stress and p66Shc in the kidney. Either endothelin antagonism or NADPH oxidase blockade partly relieves renal dysfunction through suppressing abnormal biomarkers by APQ4 KO and isoproterenol in the kidney.