Atsuhito Tone

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-β 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.

Cerebroside sulfotransferase deficiency ameliorates L-selectin-dependent monocyte infiltration in the kidney after ureteral obstruction.

Mononuclear cells infiltrating the interstitium are involved in renal tubulointerstitial injury. The unilateral ureteral obstruction (UUO) is an established experimental model of renal interstitial inflammation. In our previous study, we postulated that L-selectin on monocytes is involved in their infiltration into the interstitium by UUO and that a sulfated glycolipid, sulfatide, is the physiological L-selectin ligand in the kidney. Here we tested the above hypothesis using sulfatide- and L-selectin-deficient mice. Sulfatide-deficient mice were generated by gene targeting of the cerebroside sulfotransferase (Cst) gene. Although the L-selectin-IgG chimera protein specifically bound to sulfatide fraction in acidic lipids from wild-type kidney, it did not show such binding in fractions of Cst-/- mice kidney, indicating that sulfatide is the major L-selectin-binding glycolipid in the kidney. The distribution of L-selectin ligand in wild-type mice changed after UUO; sulfatide was relocated from the distal tubules to the peritubular capillaries where monocytes infiltrate, suggesting that sulfatide relocated to the endothelium after UUO interacted with L-selectin on monocytes. In contrast, L-selectin ligand was not detected in Cst-/- mice irrespective of UUO treatment. Compared with wild-type mice, Cst-/- mice showed a considerable reduction in the number of monocytes/macrophages that infiltrated the interstitium after UUO. The number of monocytes/macrophages was also reduced to a similar extent in L-selectin-/- mice. Our results suggest that sulfatide is a major L-selectin-binding molecule in the kidney and that the interaction between L-selectin and sulfatide plays a critical role in monocyte infiltration into the kidney interstitium.

Urinary Fetuin-A Is a Novel Marker for Diabetic Nephropathy in Type 2 Diabetes Identified by Lectin Microarray

We analyzed the urine samples of patients with type 2 diabetes at various stages of diabetic nephropathy by lectin microarray to identify a biomarker to predict the progression of diabetic nephropathy. Japanese patients with type 2 diabetes at various stages of nephropathy were enrolled and we performed lectin microarray analyses (n = 17) and measured urinary excretion of fetuin-A (n = 85). The increased signals of urine samples were observed in Siaα2-6Gal/GalNAc-binding lectins (SNA, SSA, TJA-I) during the progression of diabetic nephropathy. We next isolated sialylated glycoproteins by using SSA-lectin affinity chromatography and identified fetuin-A by liquid chromatography–tandem mass spectrometer. Urinary excretion of fetuin-A significantly increased during the progression of albuminuria (A1, 0.40±0.43; A2, 0.60±0.53; A3 1.57±1.13 ng/gCr; p = 7.29×10−8) and of GFR stages (G1, 0.39±0.39; G2, 0.49±0.45; G3, 1.25±1.18; G4, 1.34±0.80 ng/gCr; p = 3.89×10−4). Multivariate logistic regression analysis was employed to assess fetuin-A as a risk for diabetic nephropathy with microalbuminuria or GFR<60 mL/min. Fetuin-A is demonstrated as a risk factor for both microalbuminuria and reduction of GFR in diabetic nephropathy with the odds ratio of 4.721 (1.881–11.844) and 3.739 (1.785–7.841), respectively. Collectively, the glycan profiling analysis is useful method to identify the urine biomarkers and fetuin-A is a candidate to predict the progression 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.

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-tim D e 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 antiinflammatory effects on macrophages.

Comparison of insulin detemir and insulin glargine on glycemic variability in patients with type 1 and type 2 diabetes.

AIMS To compare the glycemic variability of insulin detemir and insulin glargine in type 1 and type 2 diabetic patients. METHODS 15 type 1 and 14 type 2 diabetic patients receiving intensive insulin therapy with insulin glargine were enrolled. Before and after switching insulin glargine to insulin detemir, we assessed fasting glucose variability using the standard deviation (SD) and the coefficient of variance (CV) of self-monitored fasting blood sugar (FBS) levels. RESULTS The SD and CV values were significantly decreased in type 1 diabetes after switching the therapy, though there was no significant difference in type 2 diabetes. The frequency of hypoglycemia was decreased in type 1 diabetes and there was no change in type 2 diabetes. The changes of the CV value also showed significant positive correlation with fasting serum CPR levels in all patients and total insulin dose in type 1 diabetes. The changes of frequency of hypoglycemia showed significant positive correlation with total and basal insulin dose adjusted for body weight in type 1 diabetes. CONCLUSION The present study demonstrated lower within-subject variability of insulin detemir compared to insulin glargine, suggesting that the basal insulin replacement with insulin detemir may provide a useful therapeutic strategy for uncontrolled type 1 diabetes with high glucose variability.

Computed tomography findings of congenital generalized lipodystrophy: multiple nodular fatty liver and diffuse sclerosis of bones

Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disease that is also referred to as Berardinelli-Seip syndrome. It is characterized by a lack of adipose tissue throughout the body from birth, muscular hypertrophy, advanced bone age, fatty liver, and insulin resistance. We describe computed tomography (CT) and magnetic resonance findings for a 35-year-old woman with CGL. Multiple nodular, well-defined regions of fatty infiltration of the liver are rare and have never been previously reported in a patient with lipodystrophy. To our knowledge, this is the first report describing CT findings of bone sclerotic changes associated with CGL.

A Pregnant Patient with Brittle Type 1 Diabetes Successfully Managed by CSII Therapy with Insulin Aspart

Continuous subcutaneous insulin infusion (CSII) therapy is widely accepted for brittle type 1 diabetes, since it has the benefit of less frequency of hypoglycemia and better management of the dawn phenomenon compared to multiple daily insulin injection (MDI) therapy. On the other hand, insulin aspart, one of the rapid-acting insulin analogs, was approved for Pregnancy Category B rating by the United States Food and Drug Administration (FDA) in 2007, whereas the FDA created the rating system and approved a Pregnancy Category B rating for human regular insulin in 1979.

A Case of Proinsulin-Secreting Malignant Insulinoma in an Elderly Patient with Cerebral Infarction

The diagnosis of insulinoma is sometimes challenging and the symptoms of hypoglycemia may be overlooked in elderly patients with cerebrovascular diseases and higher cerebral dysfunction. Recently, there have been an increasing number of case reports of insulinoma secreting proinsulin without hyperinsulinemia. We report a case of proinsulinsecreting malignant insulinoma in a 72-year-old man with aphasia due to cerebral infarction. He manifested no apparent symptoms, although he was incidentally found to have recurrent hypoglycemia by plasma glucose measurements. The Fajans, Grunt and Turner indexes were all within normal range and the arterial stimulation and venous sampling (ASVS) test revealed no increase in insulin concentration. However, proinsulin concentration was markedly elevated (2470 pmol/l) and well-differentiated endocrine adenocarcinoma, malignant insulinoma, with 2 cm in size in the tail of the pancreas was surgically removed. The diagnosis of hypoglycemia requires careful attention especially in elderly persons and/or patients with cerebrovascular diseases. Measurement of proinsulin is recommended in the diagnosis of insulinoma without hyperinsulinemia.

Identification of Novel Urinary Biomarkers for Predicting Renal Prognosis in Patients With Type 2 Diabetes by Glycan Profiling in a Multicenter Prospective Cohort Study: U-CARE Study 1

OBJECTIVE Because quantifying glycans with complex structures is technically challenging, little is known about the association of glycosylation profiles with the renal prognosis in diabetic kidney disease (DKD). RESEARCH DESIGN AND METHODS In 675 patients with type 2 diabetes, we assessed the baseline urinary glycan signals binding to 45 lectins with different specificities. The end point was a decrease of estimated glomerular filtration rate (eGFR) by ≥30% from baseline or dialysis for end-stage renal disease. RESULTS During a median follow-up of 4.0 years, 63 patients reached the end point. Cox proportional hazards analysis revealed that urinary levels of glycans binding to six lectins were significantly associated with the outcome after adjustment for known indicators of DKD, although these urinary glycans, except that for DBA, were highly correlated with baseline albuminuria and eGFR. Hazard ratios for these lectins were (+1 SD for the glycan index) as follows: SNA (recognizing glycan Siaα2-6Gal/GalNAc), 1.42 (95% CI 1.14–1.76); RCA120 (Galβ4GlcNAc), 1.28 (1.01–1.64); DBA (GalNAcα3GalNAc), 0.80 (0.64–0.997); ABA (Galβ3GalNAc), 1.29 (1.02–1.64); Jacalin (Galβ3GalNAc), 1.30 (1.02–1.67); and ACA (Galβ3GalNAc), 1.32 (1.04–1.67). Adding these glycan indexes to a model containing known indicators of progression improved prediction of the outcome (net reclassification improvement increased by 0.51 [0.22–0.80], relative integrated discrimination improvement increased by 0.18 [0.01–0.35], and the Akaike information criterion decreased from 296 to 287). CONCLUSIONS The urinary glycan profile identified in this study may be useful for predicting renal prognosis in patients with type 2 diabetes. Additional investigation of glycosylation changes and urinary glycan excretion in DKD is needed.