Combination of ACE inhibitor with nicorandil provides further protection in chronic kidney disease

Nicorandil protects podocytes via modulation of antioxidative capacity in acute puromycin aminonucleoside-induced nephrosis in rats

Nephrotic syndrome, characterized by proteinuria and hypoalbuminemia, results from the dysregulation of glomerular podocytes and is a significant cause of end-stage kidney disease. Patients with idiopathic nephrotic syndrome are generally treated with immunosuppressive agents; however, these agents produce various adverse effects. Previously, we reported the renoprotective effects of a stimulator of the mitochondrial ATP-dependent K⁺ channel (MitK_ATP), nicorandil, in a remnant kidney model. Nonetheless, the cellular targets of these effects remain unknown. Here, we examined the effect of nicorandil on puromycin aminonucleoside-induced nephrosis (PAN) rats, a well-established model of podocyte injury and human nephrotic syndrome. PAN was induced using a single intraperitoneal injection. Nicorandil was administered orally at 30 mg/kg/day. We found that proteinuria and hypoalbuminemia in PAN rats were significantly ameliorated following nicorandil treatment. Immunostaining and ultrastructural analysis under electron microscopy demonstrated that podocyte injury in PAN rats showed a significant partial attenuation following nicorandil treatment. Nicorandil ameliorated the increase in the oxidative stress markers nitrotyrosine and 8-hydroxy-2-deoxyguanosine in glomeruli. Conversely, nicorandil prevented the decrease in levels of the antioxidant enzyme manganese superoxide dismutase in PAN rats. We found that mitochondrial Ca²⁺ uniporter levels in glomeruli were higher in PAN rats than in control rats, and this increase was significantly attenuated by nicorandil. We conclude that stimulation of MitK_ATP by nicorandil reduces proteinuria by attenuating podocyte injury in PAN nephrosis, which restores mitochondrial antioxidative capacity, possibly through mitochondrial Ca²⁺ uniporter modulation. These data indicate that MitK_ATP may represent a novel target for podocyte injury and nephrotic syndrome.NEW & NOTEWORTHY Our findings suggest that the mitochondrial Ca²⁺ uniporter may be an upstream regulator of manganese superoxide dismutase and indicate a biochemical basis for the interaction between the ATP-sensitive K⁺ channel and Ca²⁺ signaling. We believe that our study makes a significant contribution to the literature because our results indicate that the ATP-sensitive K⁺ channel may be a potential therapeutic target for podocyte injury and nephrotic syndrome.

Nicorandil Decreases Renal Injury in Patients With Coronary Heart Disease Complicated With Type I Cardiorenal Syndrome

ABSTRACT

Cardiorenal syndrome (CRS) is a group of disorders in which heart or kidney dysfunction worsens each other. This study aimed to explore the improvement effect of nicorandil on cardiorenal injury in patients with type I CRS. Patients with coronary heart disease complicated with type I CRS were enrolled. Based on the conventional treatment, the patients were prospectively randomized into a conventional treatment group and a nicorandil group, which was treated with 24 mg/d nicorandil intravenously for 1 week. Fasting peripheral venous blood serum and urine were collected before and at the end of treatment. An automatic biochemical analyzer and enzyme linked immunosorbent assay were used to detect B-type brain natriuretic peptide (BNP), serum creatinine (Scr) and cystatin C (Cys-C), renal injury index-kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and interleukin-18 (IL-18) levels. The left ventricular ejection fraction was measured by echocardiography. All measurements were not significantly different between the nicorandil and conventional treatment groups before treatment (all P > 0.05), and BNP, Scr, Cys-C, NGAL, KIM-1, and IL-18 were decreased in the 2 groups at the end of treatment (all P < 0.05). Compared with the conventional treatment group, BNP, Scr, Cys-C, NGAL, KIM-1, and IL-18 were more significantly decreased in the nicorandil group (all P < 0.05) and left ventricular ejection fraction was more significantly increased (P < 0.05). Therefore, nicorandil could significantly improve the cardiac and renal function of patients with type I CRS. This may prove to be a new therapeutic tool for improving the prognosis and rehabilitation of type I CRS.

New progress in drugs treatment of diabetic kidney disease

Diabetic kidney disease (DKD) is not only one of the main complications of diabetes, but also the leading cause of the end-stage renal disease (ESRD). The occurrence and development of DKD have always been a serious clinical problem that leads to the increase of morbidity and mortality and the severe damage to the quality of life of human beings. Controlling blood glucose, blood pressure, blood lipids, and improving lifestyle can help slow the progress of DKD. In recent years, with the extensive research on the pathological mechanism and molecular mechanism of DKD, there are more and more new drugs based on this, such as new hypoglycemic drugs sodium-glucose cotransporter 2 (SGLT2) inhibitors, glucagon-like peptide-1 (GLP-1) inhibitors, and dipeptidyl peptidase-4 (DPP-4) inhibitors with good efficacy in clinical treatment. Besides, there are some newly developed drugs, including protein kinase C (PKC) inhibitors, advanced glycation end product (AGE) inhibitors, aldosterone receptor inhibitors, endothelin receptor (ETR) inhibitors, transforming growth factor-β (TGF-β) inhibitors, Rho kinase (ROCK) inhibitors and so on, which show positive effects in animal or clinical trials and bring hope for the treatment of DKD. In this review, we sort out the progress in the treatment of DKD in recent years, the research status of some emerging drugs, and the potential drugs for the treatment of DKD in the future, hoping to provide some directions for clinical treatment of DKD.

Hypothesis: The potential therapeutic role of nicorandil in COVID-19

At present, there is yet no specific antiviral treatment or immunization against the newly identified human severe acute respiratory syndrome virus (SARS‐CoV2) that results in a rapidly progressive pandemic coronavirus disease 2019 (COVID‐19). We believe in a crucial need for a clinical strategy to counteract this viral pandemic based on the known pathogenesis throughout the disease course. Evidence suggests that exaggerated patient's inflammatory response and oxidative stress are likely to aggravate the disease pathology. The resulting endothelial dysfunction further induces fibrosis and coagulopathy. These disturbances can generate severe acute respiratory distress syndrome (ARDS) that can progress into respiratory and circulatory failure. Nicorandil is an anti‐anginal vasodilator drug acts by increasing nitric oxide bioavailability and opening of the K_ATP channel. Recently, nicorandil has been recognized to possess multiple protective effects against tissue injury. Here, we address a possible modulatory role of nicorandil against COVID‐19 pathogenesis. We hypothesise nicorandil would be an effective form of adjuvant therapy against COVID‐19.

Histone Deacetylases Take Center Stage on Regulation of Podocyte Function

BACKGROUND

Podocytes (highly specialized and terminally differentiated epithelial cells) are integral components of the glomerular filtration barrier that are vulnerable to a variety of injuries and, as a result, they undergo a series of changes ranging from hypertrophy to detachment and apoptosis. Podocyte injury is a major determinant in proteinuric kidney disease and identification of potential therapeutic targets for preventing podocyte injury has clinical importance. Although numerous studies have achieved dramatic advances in the understanding of podocyte biology and its relevance to renal injury, few effective and specific therapies are available.

SUMMARY

Epigenetic modifications have been proven to play important roles in the pathogenesis of kidney diseases. Among them, histone deacetylase (HDAC)-mediated epigenetic acetylation in the kidney has attracted much attention, which may play multiple roles in both kidney development and the pathogenesis of kidney disease. Recent studies have demonstrated that HDAC protect against podocyte injury by regulation of inflammation, apoptosis, autophagy, mitochondrial function, and insulin resistance. In this review, we summarize recent advances in the understanding of the functions and regulatory mechanisms of HDAC in podocytes and associated proteinuric kidney diseases. In addition, we provide evidence of the potential therapeutic effects of HDAC inhibitors for proteinuric kidney disease.

KEY MESSAGES

Pharmacological targeting of HDAC-mediated epigenetic processes may open new therapeutic avenues for chronic kidney disease.

Cardio-renal protective effect of the xanthine oxidase inhibitor febuxostat in the 5/6 nephrectomy model with hyperuricemia

Although hyperuricemia has been shown to be associated with the progression of cardiovascular disorder and chronic kidney disease (CKD), there is conflicting evidence as to whether xanthine oxidase (XO) inhibitors confer organ protection besides lowering serum urate levels. In this study, we addressed the cardio-renal effects of XO inhibition in rodent CKD model with hyperuricemia. Sprague-Dawley rats underwent 5/6 nephrectomy and received a uricase inhibitor oxonic acid for 8 weeks (RK + HUA rats). In some rats, a XO inhibitor febuxostat was administered orally. Compared with control group, RK + HUA group showed a significant increase in albuminuria and renal injury. Febuxostat reduced serum uric acid as well as urinary albumin levels. Histological and immunohistochemical analysis of the kidney revealed that febuxostat alleviated glomerular, tubulointerstitial, and arteriolar injury in RK + HUA rats. Moreover, in the heart, RK + HUA showed individual myofiber hypertrophy and cardiac fibrosis, which was significantly attenuated by febuxostat. We found that renal injury and the indices of cardiac changes were well correlated, confirming the cardio-renal interaction in this model. Finally, NF-E2-related factor 2 (Nrf2) and the downstream target heme oxygenase-1 (HO-1) protein levels were increased both in the heart and in the kidney in RK + HUA rats, and these changes were alleviated by febuxostat, suggesting that tissue oxidative stress burden was attenuated by the treatment. These data demonstrate that febuxostat protects against cardiac and renal injury in RK + HUA rats, and underscore the pathological importance of XO in the cardio-renal interaction.

Effects of intracoronary injection of nicorandil and tirofiban on myocardial perfusion and short-term prognosis in elderly patients with acute ST-segment elevation myocardial infarction after emergency PCI

BACKGROUND

This study investigated the effects of the intracoronary injection of nicorandil and tirofiban on myocardial perfusion and short-term prognosis in elderly patients with acute ST-segment elevation myocardial infarction (STEMI) after emergency percutaneous coronary intervention (PCI).

METHODS

Seventy-eight STEMI patients with age >65 years who underwent emergency PCI were consecutively enrolled. These patients received conventional PCI and were randomly divided into a control group and a treatment group (n=39 per group). The control group received an intracoronary injection of tirofiban followed by a maintenance infusion for 36 hours after surgery. The treatment group received intracoronary injection of tirofiban and nicorandil, and then intravenous infusion of tirofiban and nicorandil 36 hours after surgery. The following parameters were measured: TIMI grade, corrected TIMI frame count (cTFC), TIMI myocardial perfusion grade (TMPG), ST-segment resolution (STR) rate 2 hours post-operatively, resolution of ST-segment elevation (STR) at 2 hours postoperatively, peak level of serum CK-MB, left ventricular end diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF) at 7-10 days postoperatively, and major adverse cardiac events (MACEs) in-hospital and within 30 days post-operatively.

RESULTS

Compared with the control group, more patients in the treatment group had TIMI 3 and TMPG 3, and STR after PCI was significantly higher. The treatment group also had significantly lower cTFC, lower infarction relative artery (IRA), lower peak CK-MB, and no reflow ratio after PCI. The treatment group had significantly higher LVEDD and LVEF but lower incidence of MACEs than the control group.

CONCLUSION

The intracoronary injection of nicorandil combined with tirofiban can effectively improve myocardial reperfusion in elderly STEMI patients after emergency PCI and improve short-term prognoses.

Efficacy of nicorandil on the prevention of contrast-induced nephropathy in patients with coronary heart disease undergoing percutaneous coronary intervention

OBJECTIVES

The purpose of this study was to explore the effect of nicorandil on the incidence of contrast-induced nephropathy in patients with coronary heart disease undergoing percutaneous coronary intervention.

METHODS

This study randomized 300 patients undergoing percutaneous coronary intervention to receive conventional treatment in the control group (hydration only; n = 150) vs. nicorandil therapy (nicorandil 10 mg three times daily plus hydration; n = 150). The primary endpoint was the incidence of contrast-induced nephropathy, defined as rise in serum creatinine ≥44.2 μmol/L or >25% above baseline within 72 hours after exposure to contrast administered during percutaneous coronary intervention. Secondary endpoints included differences in post-percutaneous coronary intervention serum creatinine, blood urea nitrogen, creatinine clearance rate, cystatin-C, and occurrence of major adverse events.

RESULTS

Contrast-induced nephropathy incidence was 3.3% (5/150) in the nicorandil group vs. 10.7% (16/150) in the control group (P < 0.05). At 48 and 72 hours after contrast administration, cystatin-C levels were significantly lower and creatinine clearance rate were significantly higher with nicroandil therapy compared to conventional treatment (all P values <0.05). No statistical difference was observed in the incidence of major post-procedure side effect events in hospital and fourteen days of follow-up period between the nicorandil group and control group (3.3% vs. 4.0%, P > 0.05).

CONCLUSION

Compared to conventional treatment, oral nicorandil therapy was associated with less contrast-induced nephropathy and improved renal function following contrast administration during percutaneous coronary intervention.

NO/cGMP/PKG activation protects Drosophila cells subjected to hypoxic stress

The anoxia-tolerant fruit fly, Drosophila melanogaster, has routinely been used to examine cellular mechanisms responsible for anoxic and oxidative stress resistance. Nitric oxide (NO), an important cellular signaling molecule, and its downstream activation of cGMP-dependent protein kinase G (PKG) has been implicated as a protective mechanism against ischemic injury in diverse animal models from insects to mammals. In Drosophila, increased PKG signaling results in increased survival of animals exposed to anoxic stress. To determine if activation of the NO/cGMP/PKG pathway is protective at the cellular level, the present study employed a pharmacological protocol to mimic hypoxic injury in Drosophila S2 cells. The commonly used S2 cell line was derived from a primary culture of late stage (20-24 h old) Drosophila melanogaster embryos. Hypoxic stress was induced by exposure to either sodium azide (NaN₃) or cobalt chloride (CoCl₂). During chemical hypoxic stress, NO/cGMP/PKG activation protected against cell death and this mechanism involved modulation of downstream mitochondrial ATP-sensitive potassium ion channels (mitoK_ATP). The cellular protection afforded by NO/cGMP/PKG activation during ischemia-like stress may be an adaptive cytoprotective mechanism and modulation of this signaling cascade could serve as a potential therapeutic target for protection against hypoxia or ischemia-induced cellular injury.

A preclinical overview of emerging therapeutic targets for glomerular diseases

Introduction: Animal models have provided significant insights into the mechanisms responsible for the development of glomerular lesions and proteinuria; they have also helped to identify molecules that control the podocyte function as suitable target-specific therapeutics. Areas covered: We discuss putative therapeutic targets for proteinuric glomerular diseases. An exhaustive search for eligible studies was performed in PubMed/MEDLINE. Most of the selected reports were published in the last decade, but we did not exclude older relevant milestone publications. We consider the molecules that regulate podocyte cytoskeletal dynamics and the transcription factors that regulate the expression of slit-diaphragm proteins. There is a focus on SGLT2 and sirtuins which have recently emerged as mediators of podocyte injury and repair. We also examine paracrine signallings involved in the cross-talk of injured podocytes with the neighbouring glomerular endothelial cells and parietal epithelial cells. Expert opinion: There is a need to discover novel therapeutic moleecules with renoprotective effects for those patients with glomerular diseases who do not respond completely to standard therapy. Emerging strategies targeting components of the podocyte cytoskeleton or signallings that regulate cellular communication within the glomerulus are promising avenues for treating glomerular diseases.

Metaproteomics reveals potential mechanisms by which dietary resistant starch supplementation attenuates chronic kidney disease progression in rats

BACKGROUND

Resistant starch is a prebiotic metabolized by the gut bacteria. It has been shown to attenuate chronic kidney disease (CKD) progression in rats. Previous studies employed taxonomic analysis using 16S rRNA sequencing and untargeted metabolomics profiling. Here we expand these studies by metaproteomics, gaining new insight into the host-microbiome interaction.

METHODS

Differences between cecum contents in CKD rats fed a diet containing resistant starch with those fed a diet containing digestible starch were examined by comparative metaproteomics analysis. Taxonomic information was obtained using unique protein sequences. Our methodology results in quantitative data covering both host and bacterial proteins.

RESULTS

5,834 proteins were quantified, with 947 proteins originating from the host organism. Taxonomic information derived from metaproteomics data surpassed previous 16S RNA analysis, and reached species resolutions for moderately abundant taxonomic groups. In particular, the Ruminococcaceae family becomes well resolved-with butyrate producers and amylolytic species such as R. bromii clearly visible and significantly higher while fibrolytic species such as R. flavefaciens are significantly lower with resistant starch feeding. The observed changes in protein patterns are consistent with fiber-associated improvement in CKD phenotype. Several known host CKD-associated proteins and biomarkers of impaired kidney function were significantly reduced with resistant starch supplementation. Data are available via ProteomeXchange with identifier PXD008845.

CONCLUSIONS

Metaproteomics analysis of cecum contents of CKD rats with and without resistant starch supplementation reveals changes within gut microbiota at unprecedented resolution, providing both functional and taxonomic information. Proteins and organisms differentially abundant with RS supplementation point toward a shift from mucin degraders to butyrate producers.

Different sulfonylureas induce the apoptosis of proximal tubular epithelial cell differently via closing KATP channel

BACKGROUND

Sulfonylureas (SUs) are widely prescribed for the treatment of type 2 diabetes (T2DM). Sulfonylurea receptors (SURs) are their main functional receptors. These receptors are also found in kidney, especially the tubular cells. However, the effects of SUs on renal proximal tubular epithelial cells (PTECs) were unclear.

METHODS

Three commonly used SUs were included in this study to investigate if different SUs have different effects on the apoptosis of PTECs. HK-2 cells were exposed to SUs for 24 h prior to exposure to 30 mM glucose, the apoptosis rate was evaluated by Annexin/PI flow cytometry. Bcl-2, Bax and the ratio of LC3II to LC3I were also studied by western blot in vitro. Diazoxide was used to evaluate the role of KATP channel in SUs-induced apoptosis of PTECs. A Student's t-test was used to assess significance for data within two groups.

RESULTS

Treatment with glibenclamide aggravated the apoptosis of HK-2 cells in high-glucose, as indicated by a significant decrease in the expression of Bcl-2 and increase in Bax. Additionally, the decreased LC3II/LC3I reflects that the autophagy was inhibited by glibenclamide. Similar but less pronounced change was found in glimepiride group, however, nearly opposite effects were found in gliclazide group. Further, the effects of glibenclamide on apoptosis promotion and the decreased LC3II/LC3I were ameliorated obviously by treatment with 100uM diazoxide. The potential protection effect of gliclazide was also inhibited after opening the KATP channel.

CONCLUSION

Our results suggest that, the effects of glibenclamide and glimepiride on PTECs apoptosis, especially the former, were achieved in part by closing the KATP channel. In contrast to glibenclamide and glimepiride, therapeutic concentrations of gliclazide showed an inhibitory effect on apoptosis of PTECs, which may have a benefit in the preservation of functional PTECs mass.

Renoprotective effect of topiroxostat via antioxidant activity in puromycin aminonucleoside nephrosis rats

Topiroxostat is a novel inhibitor of xanthine oxidase, and is postulated to exert a renoprotective effect. Puromycin aminonucleoside nephrosis (PAN) is a rat model of minimal change nephrotic syndrome. In this study, we examined whether topiroxostat ameliorates the kidney injury in PAN rats that was induced by a single intraperitoneal injection of PA (100 mg/kg body weight). Rats were divided into four groups: control rats, PAN rats, control rats treated with topiroxostat (1.0 mg/kg/day), and PAN rats treated with topiroxostat. Topiroxostat significantly reduced the amount of uric acid in the kidney cortex, while serum UA concentration remained unaffected by this treatment. Urinary protein excretion decreased significantly on day 10 in PAN rats upon topiroxostat treatment. Podocyte injury in PAN rats, as indicated by the reduction in WT‐1‐positive cell numbers and podocin immunoreactivity and foot process effacement, was partially yet significantly alleviated with topiroxostat treatment. In the kidney cortex, the increase in oxidative stress markers such as nitrotyrosine and 8‐hydroxy‐2‐deoxyguanosine (8‐OHdG) and the enhanced expressions of xanthine oxidase and NADPH oxidase 4 (NOX4) in PAN rats were significantly ameliorated by topiroxostat. Using cultured podocytes NOX4 expression was upregulated by adding 12 mg/dL UA into the culture medium. These results suggest that topiroxostat ameliorates proteinuria and kidney injury in PAN rats by lowering oxidative stress and tissue UA concentration. The renoprotective effects of topiroxostat could be attributed to its potential to inhibit xanthine oxidase and NOX4 in concert with suppression of intracellular UA production.

SIRT3-KLF15 signaling ameliorates kidney injury induced by hypertension

Renal fibrosis participates in the progression of hypertension-induced kidney injury. The effect of SIRT3, a member of the NAD⁺-dependent deacetylase family, in hypertensive nephropathy remains unclear. In this study, we found that SIRT3 was reduced after angiotensin II (AngII) treatment both in vivo and in vitro. Furthermore, SIRT3-knockout mice aggravated hypertension-induced renal dysfunction and renal fibrosis via chronic AngII infusion (2000 ng/kg per minute for 42 days). On the contrary, SIRT3-overexpression mice attenuated AngII-induced kidney injury compared with wild-type mice. Remarkably, a co-localization of SIRT3 and KLF15, a kidney-enriched nuclear transcription factor, led to SIRT3 directly deacetylating KLF15, followed by decreased expression of fibronectin and collagen type IV in cultured MPC-5 podocytes. In addition, honokiol (HKL), a major bioactive compound isolated from Magnolia officinalis (Houpo), suppressed AngII-induced renal fibrosis through activating SIRT3-KLF15 signaling. Taken together, our findings implicate that a novel SIRT3-KLF15 signaling may prevent kidney injury from hypertension and HKL can act as a SIRT3-KLF15 signaling activator to protect against hypertensive nephropathy.

Mito-TEMPO Alleviates Renal Fibrosis by Reducing Inflammation, Mitochondrial Dysfunction, and Endoplasmic Reticulum Stress

Background

Renal fibrosis is a common pathological symptom of chronic kidney disease (CKD). Many studies support that mitochondrial dysfunction and endoplasmic reticulum (ER) stress are implicated in the pathogenesis of CKD. In our study, we investigated the benefits and underlying mechanisms of Mito-TEMPO on renal fibrosis in 5/6 nephrectomy mice.

Methods

Mice were randomly divided into five groups as follows: control group, CKD group, CKD + Mito-TEMPO (1 mg·kg^-1·day^-1) group, CKD + Mito-TEMPO (3 mg·kg^-1·day^-1) group, and Mito-TEMPO group (3 mg·kg^-1·day^-1). Renal fibrosis was evaluated by PAS, Masson staining, immunohistochemistry, and real-time PCR. Oxidative stress markers such as SOD2 activity and MDA level in serum and isolated mitochondria from renal tissue were measured by assay kits. Mitochondrial superoxide production was evaluated by MitoSOX staining and Western blot. Mitochondrial dysfunction was assessed by electron microscopy and real-time PCR. ER stress-associated protein was measured by Western blot.

Results

Impaired renal function and renal fibrosis were significantly improved by Mito-TEMPO treatment. Furthermore, inflammation cytokines, profibrotic factors, oxidative stress markers, mitochondrial dysfunction, and ER stress were all increased in the CKD group. However, these effects were significantly ameliorated in the Mito-TEMPO treatment group.

Conclusions

Mito-TEMPO ameliorates renal fibrosis by alleviating mitochondrial dysfunction and endoplasmic reticulum stress possibly through the Sirt3-SOD2 pathway, which sheds new light on prevention of renal fibrosis in chronic kidney disease.

Diabetic Kidney Disease: Pathophysiology and Therapeutic Targets

Diabetes is a worldwide epidemic that has led to a rise in diabetic kidney disease (DKD). Over the past two decades, there has been significant clarification of the various pathways implicated in the pathogenesis of DKD. Nonetheless, very little has changed in the way clinicians manage patients with this disorder. Indeed, treatment is primarily centered on controlling hyperglycemia and hypertension and inhibiting the renin-angiotensin system. The purpose of this review is to describe the current understanding of how the hemodynamic, metabolic, inflammatory, and alternative pathways are all entangled in pathogenesis of DKD and detail the various therapeutic targets that may one day play a role in quelling this epidemic.

Renal kallikrein activation and renoprotection after dual blockade of renin-angiotensin system in diet-induced diabetic nephropathy

PURPOSE

The objective of this study is to investigate the effect of dual blockage of renin-angiotensin system (RAS) on renal kallikrein expression and inflammatory response in diabetic nephropathy (DN).

METHODS

Rats were randomly divided into 5 groups with 10 rats in each group: normal control; DN model induced by high fat and high sucrose diets; and DN treated with either benazepril 10 mg/kg/d, irbesartan 30 mg/kg/d, or both. After 8-week treatment, we examined changes in the kidney histopathology, function and immunohistochemical stain of kallikrein, macrophage marker CD68, and profibrotic markers transforming growth factor- (TGF-) β and α-smooth muscle action (SMA).

RESULTS

DN rats showed enlarged kidneys with glomerulosclerosis, interstitial chronic inflammation and fibrosis, and proteinuria. All the pathological damage and functional impairments were improved after the RAS blockades (all P < 0.05). Compared with monotherapy, combined treatment further alleviated the kidney impairments in parallel to increased tubular immunoreactivity for kallikrein and decreased immunopositive cells for CD68, TGF-β, and α-SMA.

CONCLUSION

The renoprotective effects of the dual RAS blockade in diabetic nephropathy may be attributed to improved tubular kallikrein expression and interstitial inflammatory response.