Rationale, design and baseline characteristics of the effect of canagliflozin in patients with type 2 diabetes and microalbuminuria in the Japanese population: The CANPIONE study.

AIM: To evaluate the effect of canagliflozin, a sodium-glucose co-transporter-2 (SGLT2) inhibitor, on albuminuria and the decline of estimated glomerular filtration rate (eGFR) in participants with type 2 diabetes and microalbuminuria. METHODS: The CANPIONE study is a multicentre, randomized, parallel-group and open-labelled study consisting of a unique 24-week preintervention period, during which the rate of eGFR decline before intervention is estimated, followed by a 52-week intervention and a 4-week washout period. Participants with a geometric mean urinary albumin-to-creatinine ratio (UACR) of 50 and higher and less than 300 mg/g in two consecutive first-morning voids at two different time points, and an eGFR of 45 ml/min/1.73m2 or higher, are randomly assigned to receive canagliflozin 100 mg daily or to continue guideline-recommended treatment, except for SGLT2 inhibitors. The first primary outcome is the change in UACR, and the second primary outcome is the change in eGFR slope. RESULTS: A total of 258 participants were screened and 98 were randomized at 21 sites in Japan from August 2018 to May 2021. The mean baseline age was 61.4 years and 25.8% were female. The mean HbA1c was 7.9%, mean eGFR was 74.1 ml/min/1.73m2 and median UACR was 104.2 mg/g. CONCLUSIONS: The CANPIONE study will determine whether the SGLT2 inhibitor canagliflozin can reduce albuminuria and slow eGFR decline in participants with type 2 diabetes and microalbuminuria.

Intercellular adhesion molecule-1 plays a critical role in glomerulosclerosis after subtotal nephrectomy.

BACKGROUND: Hyperfiltration in the glomeruli have been considered to be an important cause of glomerular injury; however, the role of intercellular adhesion molecule (ICAM)-1 in the pathogenesis of glomerulosclerosis is not known. METHODS: To elucidate the effects of ICAM-1 depletion on hyperfiltration-induced glomerular disorder, we used subtotally nephrectomized ICAM-1(+/+) and ICAM-1(-/-) mice. We evaluated macrophage infiltration, mesangial matrix expansion, transforming growth factor (TGF)-ß and type IV collagen accumulation in glomeruli. RESULTS: Macrophage infiltration into the glomeruli and mesangial matrix expansion coincident with increased expression of both ICAM-1 and TGF-ß, and accumulation of type IV collagen were ameliorated in subtotally nephrectomized ICAM-1(-/-) mice compared to ICAM-1(+/+) mice. ICAM-1 depletion significantly reduced hyperfiltration-induced glomerular injury after renal ablation. CONCLUSIONS: Our present findings suggest that glomerular hyperfiltration is the leading cause of glomerulosclerosis, and it is mediated, at least in part, by ICAM-1 expression and macrophage infiltration.

The macrophage is a key factor in renal injuries caused by glomerular hyperfiltration.

Glomerular hyperfiltration is a common pathway leading to glomerulosclerosis in various kinds of kidney diseases. The 5/6 renal ablation is an established experimental animal model for glomerular hyperfiltration. On the other hand, low-grade inflammation is also a common mechanism for the progression of kidney diseases including diabetic nephropathy and atherosclerosis. Here we analyzed the gene expression profile in the remnant kidney tissues of 5/6 nephrectomized mice using a DNA microarray system and compared it with that of sham-operated control mice. The 5/6 nephrectomized mice showed glomerular hypertrophy and an increase in the extracellular matrix in the glomeruli. DNA microarray analysis indicated the up-regulated expression of various kinds of genes related to the inflammatory process in remnant kidneys. We confirmed the up-regulated expression of platelet factor-4, and monocyte chemoattractant protein-1, 2, and 5 in remnant kidneys by RT-PCR. The current results suggest that the inflammatory process is involved in the progression of glomerulosclerosis and is a common pathway of the pathogenesis of kidney disease.

Endothelial barrier protection by FTY720 under hyperglycemic condition: involvement of focal adhesion kinase, small GTPases, and adherens junction proteins.

Recently, sphingosine 1-phosphate (S1P) has been highlighted as an endothelial barrier-stabilizing mediator. FTY720 is a S1P analog originally developed as a novel immunosuppressant. The phosphorylated form of FTY720 binds to S1P receptors to exert S1P-like biological effects, suggesting endothelial barrier promotion by FTY720. To elucidate whether FTY720 induces signaling events related to endothelial barrier enhancement under hyperglycemic conditions, human microvascular endothelial cells (HMVECs) preincubated with hyperglycemic (30 mM) medium were treated with 100 nM FTY720 for 3 h. Immunofluorescent microscopy and coprecipitation study revealed FTY720-induced focal adhesion kinase (FAK)-associated adherens junction (AJ) assembly at cell-cell contacts coincident with formation of a prominent cortical actin ring. FTY720 also induced transmonolayer electrical resistance (TER) augmentation in HMVEC monolayers in both normoglycemic and hyperglycemic conditions, implying endothelial barrier enhancement. Similar to S1P, site-specific FAK tyrosine phosphorylation analysis revealed FTY720-induced FAK [Y576] phosphorylation without phosphorylation of FAK [Y397/Y925]. Furthermore, FTY720 conditioned the phosphorylation profile of FAK [Y397/Y576/Y925] in hyperglycemic medium to the same pattern observed in normoglycemic medium. FTY720 challenge resulted in small GTPase Rac activation under hyperglycemic conditions, whereas increased Rho activity in hyperglycemic medium was restored to the basal level. Rac protein depletion by small interfering RNA (siRNA) technique completely abolished FTY720-induced FAK [Y576] phosphorylation. These findings strongly suggest the barrier protective effect of FTY720 on HMVEC monolayers in hyperglycemic medium via S1P signaling, further implying the possibility of FTY720 as a therapeutic agent of diabetic vascular disorder.

Macrophage scavenger receptor-a-deficient mice are resistant against diabetic nephropathy through amelioration of microinflammation.

Microinflammation is a common major mechanism in the pathogenesis of diabetic vascular complications, including diabetic nephropathy. Macrophage scavenger receptor-A (SR-A) is a multifunctional receptor expressed on macrophages. This study aimed to determine the role of SR-A in diabetic nephropathy using SR-A-deficient (SR-A(-/-)) mice. Diabetes was induced in SR-A(-/-) and wild-type (SR-A(+/+)) mice by streptozotocin injection. Diabetic SR-A(+/+) mice presented characteristic features of diabetic nephropathy: albuminuria, glomerular hypertrophy, mesangial matrix expansion, and overexpression of transforming growth factor-beta at 6 months after induction of diabetes. These changes were markedly diminished in diabetic SR-A(-/-) mice, without differences in blood glucose and blood pressure levels. Interestingly, macrophage infiltration in the kidneys was dramatically decreased in diabetic SR-A(-/-) mice compared with diabetic SR-A(+/+) mice. DNA microarray revealed that proinflammatory genes were overexpressed in renal cortex of diabetic SR-A(+/+) mice and suppressed in diabetic SR-A(-/-) mice. Moreover, anti-SR-A antibody blocked the attachment of monocytes to type IV collagen substratum but not to endothelial cells. Our results suggest that SR-A promotes macrophage migration into diabetic kidneys by accelerating the attachment to renal extracellular matrices. SR-A may be a key molecule for the inflammatory process in pathogenesis of diabetic nephropathy and a novel therapeutic target for diabetic vascular complications.

Changes of gene expression profiles in macrophages stimulated by angiotensin II--angiotensin II induces MCP-2 through AT1-receptor.

INTRODUCTION: Macrophages play critical roles in the development of atherosclerosis and diabetic nephropathy as well as many inflammatory diseases. Angiotensin II type 1 receptor antagonists (AIIA) are beneficial for the prevention of atherosclerosis and diabetic nephropathy suggesting that angiotensin II (Ang II) promotes the development of these diseases. It has recently been reported that Ang II exerts proinflammatory actions in vivo and in vitro. This study was aimed to clarify the direct effects of Ang II on monocytes/macrophages. MATERIALS AND METHODS: PMA-treated THP-1 cells, a human monocytic leukaemia cell line, were treated with Ang II (10-6 mol/L) for 24 hours with or without AIIA (CV11974). We evaluated gene expression profiles of these cells using DNA microarray system and quantified them by real-time RT-PCR. RESULTS: DNA microarray revealed that in total 19 genes, including monocyte chemoattractant protein (MCP)-2, were up-regulated by Ang II and down-regulated by AIIA. Real-time RT-PCR showed that up-regulation of MCP-2 with Ang II is blocked by the AIIA (CV11974) but not by an AT2-receptor antagonist. CONCLUSIONS: These results suggest that Ang II directly stimulates MCP-2 expression through AT1-receptors in activated macrophages. Ang II may contribute to the persistence or amplification of microinflammation in vessel walls, heart and kidney. Vasculoprotective or renoprotective effects of AIIA might partly depend on direct anti-inflammatory effects on macrophages.

Long-term efficacy and safety of vildagliptin add-on therapy in type 2 diabetes mellitus with insulin treatment.

BACKGROUND: The use of dipeptidyl peptidase (DPP)-4 inhibitors in patients with type 2 diabetes treated with insulin may be beneficial. However, the long-term efficacy and safety of vildagliptin add-on therapy in these patients remains unclear. SUBJECTS AND METHODS: A total of 73 patients with type 2 diabetes treated with insulin were randomly assigned to receive either add-on therapy of vildagliptin (n=37) or conventional therapy without DPP-4 inhibitors (n=36) for glucose control. Hemoglobin A1c (HbA1c) levels, dose and number of insulin injections, number of hypoglycemia episodes, and liver and renal function were monitored for 2years. RESULTS: The baseline characteristics of subjects, including age, dose of insulin injections, or HbA1c levels, did not differ between the two groups. In the vildagliptin group, HbA1c levels significantly decreased and the significance of HbA1c reduction was maintained for 24months (from 8.0±1.2% to 7.4±1.0%, p<0.05, at the end of observational period). In addition, the dose and number of insulin injections significantly reduced (-5.6units, p<0.01, and -0.9 times, p<0.001). However, these parameters were unchanged in the control group. The number of patients who experienced three or more episodes of hypoglycemia per year was significantly lower in the vildagliptin group (n=4) than in the control group (n=11) (odds ratio, 0.28; 95% confidence interval, 0.08-0.97; p<0.05). CONCLUSION: Vildagliptin as an add-on to insulin treatment for 24months was well tolerated and led to sustained reductions in HbA1c, the dose and number of insulin injections, and the risk of hypoglycemia.

Long-term Efficacy and Safety of Sitagliptin in Elderly Patients with Type 2 Diabetes Mellitus.

Objective We herein conducted a retrospective study to evaluate the long-term efficacy and safety of sitagliptin treatment in elderly patients with type 2 diabetes mellitus. Methods We analyzed the changes in glycemic control in 112 Japanese type 2 diabetes patients over 65 years of age treated with 50 mg/day sitagliptin. Hemoglobin A1c (HbA1c) levels, liver and kidney functions, and usage of hypoglycemic agents were recorded for 24 months. Results HbA1c levels were significantly decreased, and the significance of HbA1c reduction was maintained during the observation period [from 7.7±1.1% to 7.2±0.7% (p<0.001) at the end of observational period]. The %change in HbA1c levels was significantly and negatively correlated with the baseline HbA1c levels (r=-0.51, p<0.001), but not with age, duration of diabetes, or the estimated glomerular filtration rate (eGFR). No patient experienced severe hypoglycemia episodes, and aspartate transaminase, alanine transaminase, gamma-glutamyl transpeptidase, and the eGFR remained unchanged. The dose of sulfonylurea was finally decreased in 72% of patients treated with sulfonylurea. Conclusion Sitagliptin treatment continually decreases the HbA1c level for 24 months and is useful to reduce the dose of sulfonylurea in elderly patients with type 2 diabetes.

Practical efficacy of telmisartan for decreasing morning home blood pressure and pulse wave velocity in patients with mild-to-moderate hypertension.

The current guideline-recommended blood pressure values are difficult to maintain in general practice, partly due to the lack of ideal anti-hypertensive agents. Since morning hypertension has a high correlation with cardiovascular events, expectations that telmisartan, a long-acting angiotensin-II type-1 receptor blocker (ARB), can improve cardiovascular mortality are high. In this study, the efficiency of telmisartan in reducing morning hypertension and pulse wave velocity (PWV) as a practical surrogate endpoint was investigated. Seventeen unsupervised and 7 untreated hypertensive patients were prescribed telmisartan 40 mg/day for 3 months. Medication already prescribed upon enrollment in this study was continued, with the exception of ARBs (all of which turned out to be losartan 50 mg/day), which were discontinued and replaced with telmisartan. Morning home blood pressure (MHBP), office blood pressure (OBP), and brachial-ankle PWV (baPWV) were investigated in a prospective fashion. A stratified analysis was performed regarding previous use (group L) or non-use (group N) of losartan. Over a 3-month period, telmisartan was found to significantly reduce both OBP (from 153+/-13/85+/-9 to 141+/-17/80+/-7 mmHg (p <0.01)) and MHBP (from 153+/-23/93+/-11 to 137+/-22/82+/-10 mmHg (p <0.001)). Surprisingly, 7 patients (70%) from group L achieved an OBP of less than 140/90 mmHg by simply changing their medication to telmisartan. Furthermore, baPWV fell significantly from 1,892+/-334 cm/s to 1,672+/-324 cm/s (p <0.01), which was greater than the change in baPWV estimated by OBP reduction. Here it must be mentioned that there were no significant differences between group L and group N in the courses of blood pressures and baPWV. In conclusion, telmisartan 40 mg/day was found to be effective for reducing MHBP and arterial wall stiffness in patients with mild-to-moderate hypertension, and thus may also be effective for improving cerebrocardiovascular mortality.

The effects of telmisartan treatment on the abdominal fat depot in patients with metabolic syndrome and essential hypertension: Abdominal fat Depot Intervention Program of Okayama (ADIPO).

Telmisartan partially activates the peroxisome proliferator-activated receptor γ (PPARγ), which may ameliorate the accumulation of visceral adipose tissues and sensitise insulin action. Nineteen patients with essential hypertension and metabolic syndrome were randomly assigned to receive 40 mg of telmisartan (TELMI group) once daily or 80 mg of valsartan (VAL group) once daily for 24 weeks. The visceral fat area (VFA) measured by computed tomography (CT) was significantly reduced from 150.4±15.5 to 127.7±16.7 cm(2) in the TELMI group (p=0.049). Although VFA was also reduced in the VAL group from 169.8±14.8 to 155.3±14.8 cm(2), the change was not significant (p=0.173). There were no significant changes in body weight, body mass index (BMI), waist circumference, subdermal fat area (SFA), fasting plasma glucose, and homeostasis model assessment of insulin resistance (HOMA-IR) in comparison to the baseline and follow-up data in both groups. In conclusion, telmisartan may have a benefit in the reduction of visceral adipose tissues in comparison to valsartan.

Cholecystokinin plays a novel protective role in diabetic kidney through anti-inflammatory actions on macrophage: anti-inflammatory effect of cholecystokinin.

Inflammatory process is involved in the pathogenesis of diabetic nephropathy. In this article, we show that cholecystokinin (CCK) is expressed in the kidney and exerts renoprotective effects through its anti-inflammatory actions. DNA microarray showed that CCK was upregulated in the kidney of diabetic wild-type (WT) mice but not in diabetic intracellular adhesion molecule-1 knockout mice. We induced diabetes in CCK-1 receptor (CCK-1R) and CCK-2R double-knockout (CCK-1R(-/-),-2R(-/-)) mice, and furthermore, we performed a bone marrow transplantation study using CCK-1R(-/-) mice to determine the role of CCK-1R on macrophages in the diabetic kidney. Diabetic CCK-1R(-/-),-2R(-/-) mice revealed enhanced albuminuria and inflammation in the kidney compared with diabetic WT mice. In addition, diabetic WT mice with CCK-1R(-/-) bone marrow-derived cells developed more albuminuria than diabetic CCK-1R(-/-) mice with WT bone marrow-derived cells. Administration of sulfated cholecystokinin octapeptide (CCK-8S) ameliorated albuminuria, podocyte loss, expression of proinflammatory genes, and infiltration of macrophages in the kidneys of diabetic rats. Furthermore, CCK-8S inhibited both expression of tumor necrosis factor-α and chemotaxis in cultured THP-1 cells. These results suggest that CCK suppresses the activation of macrophage and expression of proinflammatory genes in diabetic kidney. Our findings may provide a novel strategy of therapy for the early stage of diabetic nephropathy.

P-selectin glycoprotein ligand-1 deficiency is protective against obesity-related insulin resistance.

OBJECTIVE: An inflammatory process is involved in the mechanism of obesity-related insulin resistance. Recent studies indicate that monocyte chemoattractant protein-1 (MCP-1) is a major chemokine that promotes monocyte infiltration into adipose tissues; however, the adhesion pathway in adipose tissues remains unclear. We aimed to clarify the adhesion molecules that mediate monocyte infiltration into adipose tissue. RESEARCH DESIGN AND METHODS: We used a DNA microarray to compare the gene expression profiles in epididymal white adipose tissues (eWAT) between db/db mice and C57/BL6 mice each fed a high-fat diet (HFD) or a low-fat diet (LFD). We investigated the change of insulin resistance and inflammation in eWAT in P-selectin glycoprotein ligand-1 (PSGL-1) homozygous knockout (PSGL-1⁻(/)⁻) mice compared with wild-type (WT) mice fed HFD. RESULTS: DNA microarray analysis revealed that PSGL-1, a major ligand for selectins, is upregulated in eWAT from both db/db mice and WT mice fed HFD. Quantitative real-time RT-PCR and immunohistochemistry showed that PSGL-1 is expressed on both endothelial cells and macrophages in eWAT of obese mice. PSGL-1⁻(/)⁻ mice fed HFD showed a remarkable reduction of macrophage accumulation and expression of proinflammatory genes, including MCP-1 in eWAT. Moreover, adipocyte hypertrophy, insulin resistance, lipid metabolism, and hepatic fatty change were improved in PSGL-1⁻(/) ⁻mice compared with WT mice fed HFD. CONCLUSIONS: These results indicate that PSGL-1 is a crucial adhesion molecule for the recruitment of monocytes into adipose tissues in obese mice, making it a candidate for a novel therapeutic target for the prevention of obesity-related insulin resistance.

Methotrexate prevents renal injury in experimental diabetic rats via anti-inflammatory actions.

Recent studies suggested the involvement of inflammatory processes in the pathogenesis of diabetic nephropathy. Methotrexate (MTX), a folic acid antagonist, is widely used for the treatment of inflammatory diseases. Recently, it has been shown that treatment with low-dose MTX reduces the cardiovascular mortality in patients with rheumatoid arthritis, suggesting that MTX has anti-atherosclerotic effects via its anti-inflammatory actions. This study was designed to determine the anti-inflammatory effects of this agent on diabetic nephropathy. Diabetes was induced in Sprague-Dawley rats with streptozotocin, and MTX (0.5 or 1.0 mg/kg) was administered once a week for 8 wk. Treatment with MTX reduced urinary albumin excretion, mesangial matrix expansion, macrophage infiltration, expression of TGF-beta and type IV collagen, and intercellular adhesion molecule-1 in glomeruli. MTX also reduced the high glucose-induced NF-kappaB activation in vitro and in vivo. The results indicate that intermittent administration of MTX prevented renal injuries without changes in blood glucose level and BP in experimental diabetic rats. The protective effects of MTX are suggested to be mediated by its anti-inflammatory actions through inhibition of NF-kappaB activation and consequent reduction of intercellular adhesion molecule-1 expression and macrophage infiltration. The results suggest that anti-inflammatory agents might be beneficial for the treatment of diabetic nephropathy.