Dapagliflozin Does Not Protect against Adriamycin-Induced Kidney Injury in Mice.

INTRODUCTION: Sodium-glucose cotransporter 2 (SGLT2) inhibitors target SGLT2 in renal proximal tubules and promote glycosuria in type 2 diabetes mellitus in humans and animal models, resulting in reduced blood glucose levels. Although clinical trials have shown that SGLT2 inhibitors attenuate the progression of chronic kidney disease, there have been concerns regarding SGLT2-induced acute kidney injury. In this study, we investigated the effect of SGLT2 inhibitors on adriamycin-induced kidney injury in mice. METHODS: Seven-week-old balb/c mice were injected with adriamycin 11.5 mg/kg via the tail vein. Additionally, dapagliflozin was administered via gavage for 2 weeks. The mice were divided into five groups: vehicle, dapagliflozin 3 mg/kg, adriamycin, adriamycin plus dapagliflozin 1 mg/kg, and adriamycin plus dapagliflozin 3 mg/kg. RESULTS: Adriamycin injection reduced the body weight and food and water intakes. Dapagliflozin also decreased the body weight and food and water intakes. Fasting blood glucose and urine volume were not altered by either adriamycin or dapagliflozin. Once adriamycin-induced kidney injury had developed, there were no differences in systolic blood pressure among the groups. Dapagliflozin did not alleviate proteinuria in adriamycin-induced kidney injury. Adriamycin induced significant glomerular and interstitial injury, but dapagliflozin did not attenuate these changes in renal injury. Interestingly, SGLT2 expressions were different between the cortex and medulla of kidneys by dapagliflozin treatment. Dapagliflozin increased SGLT2 expression in medulla, not in cortex. CONCLUSION: Dapagliflozin had no effect on proteinuria or inflammatory changes such as glomerular and tubular damages in adriamycin-induced kidney injury. Our study suggests that dapagliflozin does not protect against adriamycin-induced kidney injury. More experimental studies regarding the effects of SGLT2 inhibitors on various kidney diseases are needed to clarify the underlying mechanisms.

Adaptive Nutrition Intervention Stabilizes Serum Phosphorus Levels in Hemodialysis Patients: A Multicenter Decentralized Clinical Trial Using Real-World Data.

OBJECTIVE: This study aims to evaluate the effect of an adaptive nutritional and educational intervention for patients on hemodialysis (HD) in a routine care setting, using real-world data from electronic health records. METHODS: Decentralized clinical trial of seven HD facilities recruited patients who have been on HD for over 3 months (N = 153) for an 8-week adaptive intervention protocol. Patients were divided into four groups: (1) control (2) education intervention (3) meal intervention (4) education and meal interventions. Educational contents were digitally delivered via mobile phones and premade meals tailored on laboratory findings were home-delivered. Changes in serum electrolytes and malnutrition inflammation score (MIS) were analyzed. RESULTS: Meal intervention statistically significantly stabilized serum phosphorus level (ß = -0.81 mg/dL, 95% confidence interval = [-1.40, -0.22]) at week 8, with increased likelihood of being within target serum value range (odds ratio = 1.21, 95% confidence interval = [1.04, 1.40]). Meal group showed better nutritional status (MIS = 3.65) than the education group (MIS = 5.10) at week 8 (adjusted p < .05). No significant changes were observed in serum potassium level, depression, and self-efficacy. CONCLUSION: It was demonstrated that an adaptive meal intervention in a real-world care setting may benefit serum phosphorus control and nutritional status of patients on HD, without negative effect on depression levels or self-efficacy. More work is needed to develop an effective educational intervention.

Role of NADPH Oxidases in Renal Aging.

INTRODUCTION: Aging of the kidney is associated with complex molecular, histological, and functional changes. Although the aging process itself does not induce renal damage, underlying disease such as diabetes mellitus can aggravate kidney injury during aging. Although oxidative stress is considered an important mediator in age-related renal fibrosis, it is unclear how oxidative stress increases during normal and diabetic aging. METHODS: In this study, we investigated molecular changes in the kidney in normal and diabetic aging mice. C57BL/6 mice were studied at 2, 12, and 24 months of age, and leptin receptor-deficient db/db mice were studied at 8, 12, 16, 20, 24, and 38 weeks of age. We measured renal functional parameters, fibrotic and inflammatory markers, and oxidative stress markers at all the above time points. RESULTS: Both nondiabetic and diabetic mice exhibited progressive microalbuminuria during their lifespan. Interestingly, both diabetic aging and normal aging mice showed progressive increases in oxidative stress markers such as plasma and urinary 8-isoprostane, as well as renal lipid hydroperoxide content. In renal tissues, proinflammatory and profibrotic molecules were significantly upregulated in an age-dependent manner. Expression of three NADPH oxidase (Nox) isoforms, namely, Nox1, Nox2, and Nox4, was significantly increased during aging. Compared with normal aging mice, diabetic db/db mice demonstrated more dramatic changes during aging process. CONCLUSIONS: Our findings suggest that NADPH oxidases play an important role in the aging kidney under both normal and diabetic conditions. Targeting of these oxidases might be a new promising therapy to treat issues associated with aging kidneys.

APX-115, a first-in-class pan-NADPH oxidase (Nox) inhibitor, protects db/db mice from renal injury.

Recent studies have suggested that renal Nox is important in the progression of diabetic nephropathy. Therefore, we investigated the effect of a novel pan-NOX-inhibitor, APX-115, on diabetic nephropathy in type 2 diabetic mice. Eight- week-old db/m and db/db mice were treated with APX-115 for 12 weeks. APX-115 was administered by oral gavage at a dose of 60 mg/kg per day. To compare the effects of APX-115 with a dual Nox1/Nox4 inhibitor, db/db mice were treated with GKT137831 according to the same protocol. APX-115 significantly improved insulin resistance in diabetic mice, similar to GKT137831. Oxidative stress as measured by plasma 8-isoprostane level was decreased in the APX-115 group compared with diabetic controls. All lipid profiles, both in plasma and tissues improved with Nox inhibition. APX-115 treatment decreased Nox1, Nox2, and Nox4 protein expression in the kidney. APX-115 decreased urinary albumin excretion and preserved creatinine level. In diabetic kidneys, APX-115 significantly improved mesangial expansion, but GKT137831 did not. In addition, F4/80 infiltration in the adipose tissue and kidney decreased with APX-115 treatment. We also found that TGF-ß stimulated ROS generation in primary mouse mesangial cells (pMMCs) from wild-type, Nox1 KO, and Duox1 KO mice, but did not induce Nox activity in pMMCs from Nox2 knockout (KO), Nox4 KO, or Duox2 KO mice. These results indicate that activating Nox2, Nox4, or Duox2 in pMMCs is essential for TGF-ß-mediated ROS generation. Our findings suggest that APX-115 may be as effective or may provide better protection than the dual Nox1/Nox4 inhibitor, and pan-Nox inhibition with APX-115 might be a promising therapy for diabetic nephropathy.

DA-1229, a dipeptidyl peptidase IV inhibitor, protects against renal injury by preventing podocyte damage in an animal model of progressive renal injury.

Although dipeptidyl peptidase IV (DPPIV) inhibitors are known to have renoprotective effects, the mechanism underlying these effects has remained elusive. Here we investigated the effects of DA-1229, a novel DPPIV inhibitor, in two animal models of renal injury including db/db mice and the adriamycin nephropathy rodent model of chronic renal disease characterized by podocyte injury. For both models, DA-1229 was administered at 300 mg/kg/day. DPPIV activity in the kidney was significantly higher in diabetic mice compared with their nondiabetic controls. Although DA-1229 did not affect glycemic control or insulin resistance, DA-1229 did improve lipid profiles, albuminuria and renal fibrosis. Moreover, DA-1229 treatment resulted in decreased urinary excretion of nephrin, decreased circulating and kidney DPPIV activity, and decreased macrophage infiltration in the kidney. In adriamycin-treated mice, DPPIV activity in the kidney and urinary nephrin loss were both increased, whereas glucagon-like peptide-1 concentrations were unchanged. Moreover, DA-1229 treatment significantly improved proteinuria, renal fibrosis and inflammation associated with decreased urinary nephrin loss, and kidney DPP4 activity. In cultured podocytes, DA-1229 restored the high glucose/angiotensin II-induced increase of DPPIV activity and preserved the nephrin levels in podocytes. These findings suggest that activation of DPPIV in the kidney has a role in the progression of renal disease, and that DA-1229 may exert its renoprotective effects by preventing podocyte injury.

Chronic Administration of Visfatin Ameliorated Diabetic Nephropathy in Type 2 Diabetic Mice.

BACKGROUND/AIMS: Visfatin is a known adipokine which may improve insulin resistance in obesity and have an anti-diabetic effect via the insulin receptor. We studied the effects of visfatin on diabetic nephropathy in type 2 diabetic mice. METHODS: Diabetic male db/db mice were treated with intraperitoneal injections of visfatin. Basal parameters were measured in all mice and glucose tolerance test (GTT) and insulin tolerance test (ITT) were performed in diabetic mice. The histopathological and molecular changes were evaluated in diabetic nephropathy. RESULTS: Visfatin treatment had no effect on body weight, water and food intake, urinary volume, blood glucose, and HbA1c level. However, visfatin improved HOMA-IR, GTT, ITT and decreased plasma insulin and visfatin level, but not adiponectin level. Plasma cholesterol and triglyceride level were also improved by visfatin treatment. Significantly, visfatin decreased albuminuria in diabetic mice. Glomerulosclerotic change and mesangial expansion in the kidneys were significantly reduced. In addition, visfatin inhibited the expression of proinflammatory and profibrotic cytokines such as MCP-1, TGFß1, type IV collagen, and PAI-1. The enzymes related to lipid metabolism in the kidney, HMG-CoAR was suppressed by visfatin treatment, whereas FXR and ABCA1 were significantly elevated by treatment. CONCLUSION: Visfatin might have a protective effect in diabetic nephropathy without the hypoglycemic effect.

Renoprotective Effects of a Highly Selective A3 Adenosine Receptor Antagonist in a Mouse Model of Adriamycin-induced Nephropathy.

The concentration of adenosine in the normal kidney increases markedly during renal hypoxia, ischemia, and inflammation. A recent study reported that an A3 adenosine receptor (A3AR) antagonist attenuated the progression of renal fibrosis. The adriamycin (ADX)-induced nephropathy model induces podocyte injury, which results in severe proteinuria and progressive glomerulosclerosis. In this study, we investigated the preventive effect of a highly selective A3AR antagonist (LJ1888) in ADX-induced nephropathy. Three groups of six-week-old Balb/c mice were treated with ADX (11 mg/kg) for four weeks and LJ1888 (10 mg/kg) for two weeks as following: 1) control; 2) ADX; and 3) ADX + LJ1888. ADX treatment decreased body weight without a change in water and food intake, but this was ameliorated by LJ1888 treatment. Interestingly, LJ1888 lowered plasma creatinine level, proteinuria, and albuminuria, which had increased during ADX treatment. Furthermore, LJ1888 inhibited urinary nephrin excretion as a podocyte injury marker, and urine 8-isoprostane and kidney lipid peroxide concentration, which are markers of oxidative stress, increased after injection of ADX. ADX also induced the activation of proinflammatory and profibrotic molecules such as TGF-ß1, MCP-1, PAI-1, type IV collagen, NF-κB, NOX4, TLR4, TNFα, IL-1ß, and IFN-γ, but they were remarkably suppressed after LJ1888 treatment. In conclusion, our results suggest that LJ1888 has a renoprotective effect in ADX-induced nephropathy, which might be associated with podocyte injury through oxidative stress. Therefore, LJ1888, a selective A3AR antagonist, could be considered as a potential therapeutic agent in renal glomerular diseases which include podocyte injury and proteinuria.

Dipeptidyl peptidase IV inhibitor protects against renal interstitial fibrosis in a mouse model of ureteral obstruction.

Dipeptidyl peptidase IV (DPPIV) is an exopeptidase that modulates the function of several substrates, among which insulin-releasing incretin hormones are the most well known. DPPIV also modulate substrates involved in inflammation, cell migration, and cell differentiation. Although DPPIV is highly expressed in proximal renal tubular cells, the role of DPPIV inhibition in renal disease is not fully understood. For this reason, we investigated the effects of LC15-0444, a DPPIV inhibitor, on renal function in a mouse model of renal fibrosis. Eight-week-old C57/BL6 mice were subjected to unilateral ureteral obstruction (UUO) and were treated with LC15-0444 (a DPPIV inhibitor) at a dose of 150 mg/kg per day in food or vehicle for 14 days. DPPIV activity was significantly increased in obstructed kidneys, and reduced after treatment with LC15-0444. Administration of LC15-0444 resulted in a significant decrease in albuminuria, urinary excretion of 8-isoprostane, and renal fibrosis. DPPIV inhibition also substantially decreased the synthesis of several proinflammatory and profibrotic molecules, as well as the infiltration of macrophages. UUO significantly increased, and LC15-0444 markedly suppressed, levels of phosphorylated Smad2/3, TGFß1, toll-like receptor 4, high-mobility group box-1, NADPH oxidase 4, and NF-κB. These results suggest that activation of DPPIV in the kidney has a role in the progression of renal disease and that targeted therapy inhibiting DPPIV may prove to be a useful new approach in the management of progressive renal disease, independent of mechanisms mediated by glucagon-like peptide-1.

Kidney Health Plan 2033 in Korea: bridging the gap between the present and the future.

In response to the increase in the prevalence of chronic kidney disease (CKD) in Korea, the growth of patients requiring renal replacement therapy and the subsequent increase in medical costs, the rapid expansion of patients with end-stage kidney disease (ESKD), and the decrease in patients receiving home therapy, including peritoneal dialysis, the Korean Society of Nephrology has proclaimed the new policy, Kidney Health Plan 2033 (KHP 2033). KHP 2033 would serve as a milestone to bridge the current issues to a future solution by directing the prevention and progression of CKD and ESKD, particularly diabetic kidney disease, and increasing the proportion of home therapy, thereby reducing the socioeconomic burden of kidney disease and improving the quality of life. Here, we provide the background for the necessity of KHP 2033, as well as the contents of KHP 2033, and enlighten the Korean Society of Nephrology's future goals. Together with patients, healthcare providers, academic societies, and national policymakers, we need to move forward with goal-oriented drive and leadership to achieve these goals.

Glucocorticoids attenuate septic acute kidney injury.

BACKGROUND: The incidence and mortality of septic acute kidney injury (AKI) remains high, whereas our understanding of pathogenesis for septic AKI is still limited. Glucocorticoids (GCs) have been clinically recommended for treatment of septic shock and also have showed favorable effect on septic AKI in several animal experiments. The aim of this study is to investigate the pathophysiology of septic AKI and the effect of GCs on septic AKI. METHODS: We induced septic AKI using cecal ligation and puncture (CLP) model in 8-10 wk-old male C57BL/6 mice. Saline or dexamethasone (2.5 mg/kg) dissolved in saline was administered after surgery. Hemodynamic, biochemical and histological changes were examined in a time-course manner. RESULTS: CLP resulted in hyperdynamic warm shock with multiple organ dysfunction including AKI. Despite renal dysfunction, light microscopy showed scanty acute tubular necrosis and inflammation. Instead, CLP induced significant increase in apoptosis of the kidney and spleen cells. In addition, septic kidneys showed mitochondrial injury and alterations in Bcl2 family proteins in the renal tubular cells. Dexamethasone treatment attenuated renal dysfunction, but it was not associated with improvement of hemodynamic parameters. Dexamethasone-induced organ protective effect was associated with reduced mitochondrial injury with preserved cytochrome c oxidase and suppression of proapoptotic proteins as well as reduced cytokine release. CONCLUSIONS: Mitochondrial damage and subsequent apoptosis are thought to play important role in the development of septic AKI. GCs might be a useful therapeutic strategy for septic AKI by reducing mitochondrial damage and apoptosis.

The Role of V-Set Ig Domain-Containing 4 in Chronic Kidney Disease Models.

V-set Ig domain-containing 4 (VSIG4) regulates an inflammatory response and is involved in various diseases. However, the role of VSIG4 in kidney diseases is still unclear. Here, we investigated VSIG4 expression in unilateral ureteral obstruction (UUO), doxorubicin-induced kidney injury mouse, and doxorubicin-induced podocyte injury models. The levels of urinary VSIG4 protein significantly increased in the UUO mice compared with that in the control. The expression of VSIG4 mRNA and protein in the UUO mice was significantly upregulated compared with that in the control. In the doxorubicin-induced kidney injury model, the levels of urinary albumin and VSIG4 for 24 h were significantly higher than those in the control mice. Notably, a significant correlation was observed between urinary levels of VSIG4 and albumin (r = 0.912, p < 0.001). Intrarenal VSIG4 mRNA and protein expression were also significantly higher in the doxorubicin-induced mice than in the control. In cultured podocytes, VSIG4 mRNA and protein expressions were significantly higher in the doxorubicin-treated groups (1.0 and 3.0 µg/mL) than in the controls at 12 and 24 h. In conclusion, VSIG4 expression was upregulated in the UUO and doxorubicin-induced kidney injury models. VSIG4 may be involved in pathogenesis and disease progression in chronic kidney disease models.

Puromycin-induced kidney injury and subsequent regeneration in adult zebrafish.

Puromycin treatment can cause glomerular injury to the kidney, leading to proteinuria. However, the pathogenesis of acute kidney injury and subsequent regeneration after puromycin administration in animal models remain unclear. In this work, we examined the characteristics of kidney injury and subsequent regeneration following puromycin treatment in adult zebrafish. We intraperitoneally injected 100 µg of puromycin into zebrafish; sacrificed them at 1, 3, 5, 7, or 14 days post-injection (dpi); and examined the morphological, functional, and molecular changes in the kidney. Puromycin-treated zebrafish presented more rapid clearance of rhodamine dextran than control animals. Morphological changes were observed immediately after the puromycin injection (1-7 dpi) and had recovered by 14 dpi. The mRNA production of lhx1a, a renal progenitor marker, increased during recovery from kidney injury. Levels of NFκB, TNFα, Nampt, and p-ERK increased significantly during nephron injury and regeneration, and Sirt1, FOXO1, pax2, and wt1b showed an increasing tendency. However, TGF-ß1 and smad5 production did not show any changes after puromycin treatment. This study provides evidence that puromycin-induced injury in adult zebrafish kidneys is a potential tool for evaluating the mechanism of nephron injury and subsequent regeneration.

SH3YL1 Protein Predicts Renal Outcomes in Patients with Type 2 Diabetes.

NADPH oxidase (NOX)-derived oxidative stress is an important factor in renal progression, with NOX4 being the predominant NOX in the kidney. Recently, Src homology 3 (SH3) domain-containing YSC84-like 1 (SH3YL1) was reported to be a regulator of NOX4. In this study, we tested whether the SH3YL1 protein could predict 3-year renal outcomes in patients with type 2 diabetes. A total of 131 patients with type 2 diabetes were enrolled in this study. Renal events were defined as a 15% decline in the estimated glomerular filtration rate (eGFR) from the baseline, the initiation of renal replacement therapy, or death during the 3 years. The levels of the urinary SH3YL1-to-creatinine ratio (USCR) were significantly different among the five stages of chronic kidney disease (CKD) and the three groups, based on albuminuria levels. The USCR levels showed a significant negative correlation with eGFR and a positive correlation with the urinary albumin-to-creatinine ratio (UACR). Plasma SH3YL1 levels were significantly correlated with UACR. The highest tertile group of USCR and plasma SH3YL1 had a significantly lower probability of renal event-free survival. Furthermore, the highest tertile group of USCR showed a significant association with the incidence of renal events after full adjustment: adjusted hazard ratio (4.636: 95% confidence interval, 1.416-15.181, p = 0.011). This study suggests that SH3YL1 is a new diagnostic biomarker for renal outcomes in patients with type 2 diabetes.

Pan-Nox inhibitor treatment improves renal function in aging murine diabetic kidneys.

Background: Aging is a risk factor for development of chronic kidney disease and diabetes mellitus with commonly shared features of chronic inflammation and increased oxidative stress. Here, we investigated the effect of pan-Nox-inhibitor, APX-115, on renal function in aging diabetic mice. Methods: Diabetes was induced by intraperitoneal injection of streptozotocin at 50 mg/kg/day for 5 days in 52-week-old C57BL/6J mice. APX-115 was administered by oral gavage at a dose of 60 mg/kg/day for 12 weeks in nondiabetic and diabetic aging mice. Results: APX-115 significantly improved insulin resistance in diabetic aging mice. Urinary level of 8-isoprostane was significantly increased in diabetic aging mice than nondiabetic aging mice, and APX-115 treatment reduced 8-isoprostane level. Urinary albumin and nephrin excretion were significantly higher in diabetic aging mice than nondiabetic aging mice. Although APX-115 did not significantly decrease albuminuria, APX-115 markedly improved mesangial expansion, macrophage infiltration, and expression of fibrosis molecules such as transforming growth factor beta 1 and plasminogen activator inhibitor 1. Interestingly, the expression of all Nox isoforms including Nox1, Nox2, and Nox4 was significantly increased in diabetic aging kidneys, and APX-115 treatment decreased Nox1, Nox2, and Nox4 protein expression in the kidney. Furthermore, Klotho expression was significantly decreased in diabetic aging kidneys, and APX-115 restored Klotho level. Conclusion: Our results provide evidence that pan-Nox inhibition may improve systemic insulin resistance and decrease oxidative stress, inflammation, and fibrosis in aging diabetic status and may have potential protective effects on aging diabetic kidney.

Spexin-based galanin receptor 2 agonist improves renal injury in mice with type 2 diabetes.

The spexin-based GALR2 agonist (NS200) is a novel drug, which has shown antidepressant and anxiolytic action in a recent experimental study. In this study, we investigated the effects of NS200 on renal injury in an animal model of type 2 diabetes. Eight-week-old diabetic db/db mice were administered NS200 for 12 weeks. NS200 was intraperitoneally administered at a dose of 1.0 mg/kg/day. Metabolic parameters and structural and molecular changes in the kidneys were compared among the three groups: non-diabetic db/m control, db/db mice, and NS200-treated db/db mice. In db/db mice, NS200 administration did not impact the body weight, food and water intake, urinary volume, fasting blood glucose level, or HbA1c levels. Insulin and glucose tolerance were also unaffected by NS200 treatment. However, NS200 improved urinary albumin excretion and glomerulosclerosis in diabetic kidneys. Activation of TGFß1 and insulin signaling pathways, such as PI3 K /AKT/ERK, were inhibited by NS200. In conclusion, a spexin-based GALR2 agonist attenuated diabetic nephropathy by alleviating renal fibrosis in mice with type 2 diabetes. Spexin-based GALR2 agonists have considerable potential as novel treatment agents in diabetic nephropathy.

Adenosine receptors as emerging therapeutic targets for diabetic kidney disease.

Diabetic kidney disease (DKD) is now a pandemic worldwide, and novel therapeutic options are urgently required. Adenosine, an adenosine triphosphate metabolite, plays a role in kidney homeostasis through interacting with four types of adenosine receptors (ARs): A1AR, A2AAR, A2BAR, and A3AR. Increasing evidence highlights the role of adenosine and ARs in the development and progression of DKD: 1) increased adenosine in the plasma and urine of diabetics with kidney injury, 2) increased expression of each of the ARs in diabetic kidneys, 3) the protective effect of coffee, a commonly ingested nonselective AR antagonist, on DKD, and 4) the protective effect of AR modulators in experimental DKD models. We propose AR modulators as a new therapeutic option to treat DKD. Detailed mechanistic studies on the pharmacology of AR modulators will help us to develop effective first-in-class AR modulators against DKD.

Upregulation of VSIG4 in Type 2 Diabetic Kidney Disease.

Fibrosis is the final common finding in patients with advanced diabetic kidney disease. V-set Ig domain containing 4 (VSIG4) is related to fibrosis in several diseases. It also contributes to fibrosis under high-glucose conditions in renal tubule cells. To determine the role of VSIG4 in type 2 diabetes, we examined VSIG4 expression in a type 2 diabetic animal model and podocyte. Urinary excretion of albumin and VSIG4 was significantly higher in db/db mice than in the control group. Urine VSIGs levels for 6 h were about three-fold higher in db/db mice than in db/m mice at 20 weeks of age: 55.2 ± 37.8 vs. 153.1 ± 74.3 ng, p = 0.04. Furthermore, urinary VSIG4 levels were significantly correlated with urinary albumin levels (r = 0.77, p < 0.01). Intrarenal VSIG4 mRNA expression was significantly higher in db/db mice than in control mice (1.00 ± 0.35 vs. 1.69 ± 0.77, p = 0.04). Further, VSIG4 expression was almost twice as high in db/db mice at 20 weeks of age. Intrarenal VSIG immunoreactivity in db/db mice was also significantly higher than that in control mice. In cultured podocytes, both high glucose and angiotensin II significantly upregulated the expression of VSIG4 mRNA and protein. In conclusion, VSIG4 was upregulated in an animal model of type 2 diabetes and was related to albuminuria and pro-fibrotic markers. Considering these relationships, VSIG4 may be an important mediator of diabetic nephropathy progression.

Blood Pressure Control in Patients with Diabetic Kidney Disease.

Diabetic kidney disease (DKD) is the most common cause of end-stage kidney disease. Blood pressure (BP) control can reduce the risks of cardiovascular (CV) morbidity, mortality, and kidney disease progression. Recently, the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines have suggested the implementation of a more intensive BP control with a target systolic BP (SBP) of <120 mmHg based on the evidence that the CV benefits obtained is outweighed by the kidney injury risk associated with a lower BP target. However, an extremely low BP level may paradoxically aggravate renal function and CV outcomes. Herein, we aimed to review the existing literature regarding optimal BP control using medications for DKD.

Aliskiren improves insulin resistance and ameliorates diabetic vascular complications in db/db mice.

BACKGROUND: Aliskiren is a direct renin inhibitor (DRI) and provides an organ-protective effect in human and animal experiments. However, there is no current evidence of the effect of DRI on insulin resistance and metabolic abnormalities in type 2 diabetic animals. Methods. We investigated the effects and molecular mechanism of aliskiren in db/db mice and cultured mesangial cells (MCs). RESULTS: Aliskiren treatment for 3 months at a dose of 25 mg/kg/day via an osmotic mini-pump did not induce significant changes in blood glucose levels, systolic blood pressure, serum creatinine and electrolyte levels. However, aliskiren treatment improved insulin resistance confirmed by insulin tolerance test and various biomarkers including homeostasis model assessment index levels and lipid abnormalities. The treated group also exhibited significant improvement in cardiac functional and morphological abnormalities including left ventricular hypertrophy, and induced phenotypic changes in adipose tissue. Aliskiren treatment also markedly decreased urinary albumin excretion, glomerulosclerosis and suppressed profibrotic and proinflammatory cytokine synthesis and improved renal lipid metabolism. In cultured MCs, high glucose stimulation increased MC renin concentration. Furthermore, renin treatment directly up-regulates synthesis of proinflammatory and profibrotic cytokines, which were abolished by prior treatment with aliskiren and angiotensin receptor (AT1) antagonist. These results suggest that the beneficial effect of aliskiren is mediated by an angiotensin-dependent mechanism. CONCLUSIONS: Together, these results imply that aliskiren provides an organ-protective effect through improvement in insulin resistance and lipid abnormality, as well as direct anti-fibrotic effect in target organ in db/db mice. Aliskiren may be a useful new therapeutic agent in the treatment of type 2 diabetes mellitus and diabetic nephropathy.

Farnesoid X receptor (FXR) agonist ameliorates systemic insulin resistance, dysregulation of lipid metabolism, and alterations of various organs in a type 2 diabetic kidney animal model.

BACKGROUND: Farnesoid X receptor (FXR) plays a role in homeostasis of bile acid, lipid, and carbohydrate metabolism. However, the systemic effects of FXR in diabetic nephropathy are controversial. We aimed to clarify the systemic effects of FXR on various organs in a type 2 diabetic animal model. METHODS: We treated db/db mice with the FXR agonist GW4064 for 3 months and evaluated insulin resistance, lipid metabolism, renal functional changes, and structural changes in organs including those of the kidney, liver, pancreas, adipose tissue, aorta, and heart. RESULTS: The FXR agonist significantly improved plasma lipid profiles and insulin resistance and showed beneficial systemic effects on several organs. In the kidney, the FXR agonist ameliorated albuminuria, pro-fibrotic and pro-inflammatory changes and improved renal lipid metabolism. These changes were also associated with a decrease in lipid hydroperoxide in the kidney. Similar beneficial effects were shown in other organs, including restoration of pancreatic beta cell hypertrophy, hepatic steatosis and aortic medial hypertrophy, more differentiated phenotypic changes in adipose tissue, and improvement of cardiomyocyte disarray and left ventricular mass index. CONCLUSIONS: The FXR agonist improves insulin resistance, renal lipid metabolism, and functional and structural changes in the kidney and other organs.