Increased expression of intercellular adhesion molecule-1 (ICAM-1) in diabetic rat glomeruli: glomerular hyperfiltration is a potential mechanism of ICAM-1 upregulation

Sodium tungstate (NaW) decreases inflammation and renal fibrosis in diabetic nephropathy

BACKGROUND

Diabetic Nephropathy is one of the most severe complications of Diabetes Mellitus and the main cause of end-stage kidney disease worldwide. Despite the therapies available to control blood glucose and blood pressure, many patients continue to suffer from progressive kidney damage. Chronic hyperglycemia is the main driver of changes observed in diabetes; however, it was recently discovered that inflammation and oxidative stress contribute to the development and progression of kidney damage. Therefore, it is important to search for new pharmacological therapies that stop the progression of DN. Sodium tungstate (NaW) is an effective short and long-term antidiabetic agent in both type 1 and type 2 diabetes models.

METHODS

In this study, the effect of NaW on proinflammatory signalling pathways, proinflammatory proteins and fibrosis in the streptozotocin (STZ)-induced type 1 diabetic rat model was analysed using histological analysis, western blotting and immunohistochemistry.

RESULTS

NaW treatment in diabetic rats normalize parameters such as glycemia, glucosuria, albuminuria/creatinuria, glomerular damage, and tubulointerstitial damage. NaW decreased the proinflammatory signaling pathway NF-κB, inflammatory markers (ICAM-1, MCP-1 and OPN), profibrotic pathways (TGFβ1/Smad2/3), reduced epithelial-mesenchymal transition (α -SMA), and decreased renal fibrosis (type IV collagen).

CONCLUSION

NaW could be an effective drug therapy for treating human diabetic nephropathy.

Association of major candidate protein biomarkers and long-term diabetic kidney disease progression among Asians with young-onset type 2 diabetes mellitus

AIMS

We aim to determine the association of seven major candidate protein biomarkers and diabetic kidney disease (DKD) progression among Asians with young-onset type 2 diabetes mellitus (T2DM).

METHODS

824 T2DM patients (onset ≤ 40 years old) were classified as DKD progressors based on yearly estimated glomerular filtration rate (eGFR) decline of >3 ml/min/1.73 m2 or >40 % from baseline. Plasma leucine-rich α-2-glycoprotein 1 (pLRG1), tumor necrosis factor-receptor 1 (pTNF-R1), pigment epithelium-derived factor (pPEDF), urinary α-1-microglobulin (uA1M), kidney injury molecular 1 (uKIM-1), haptoglobin (uHP) and uromodulin (uUMOD) were measured using enzyme-linked immunoassays.

RESULTS

Over 5.7 years of follow-up, 25.2 % of patients were DKD progressors. Elevated levels of pLRG1, pTNF-R1, pPEDF, uA1M, uKIM-1 and uHP were associated with DKD progression. The association between pTNF-R1 levels and DKD progression persisted after adjusting for clinical covariates (OR 1.84, 95 %CI 1.44-2.34, p < 0.001). The effects of pTNF-R1 were partially mediated through hyperglycemia (8 %) and albuminuria (10 %). Inclusion of pTNF-R1 in a clinical variable-based model improved the area under the receiver operating characteristics curve for predicting DKD progression by 0.02, from 0.72 (95 %CI 0.68-0.76) to 0.74 (95 %CI 0.70-0.78), p = 0.099.

CONCLUSIONS

Among seven major candidate proteins, pTNF-R1, partially mediated through hyperglycemia and albuminuria, robustly predicted DKD progression among Asians with young-onset T2DM.

Emerging therapeutic landscape: Incretin agonists in chronic kidney disease management

The increasing incidence of chronic kidney disease (CKD) poses a significant public health concern, prompting heightened attention to its treatment. Incretins, including glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide, are intestinal peptides released after nutrient intake, known for their hypoglycemic effects in diabetes management. Recent advancements highlight the promising outcomes of GLP-1 receptor agonists in reducing CKD risk factors and improving renal outcomes. The multifaceted functions of GLP-1, such as its anti-obesity, anti-hypertensive, anti-hyperglycemic, anti-lipid, anti-inflammatory, and endothelial function protective properties, contribute to its potential as a therapeutic agent for CKD. Although experiments suggest the potential benefits of incretin in CKD, a comprehensive understanding of its specific mechanisms is still lacking. This review aims to provide a detailed examination of current evidence and potential future directions, emphasizing the promising yet evolving landscape of incretin agonists in the context of CKD.

Roles and crosstalks of macrophages in diabetic nephropathy

Diabetic nephropathy (DN) is the most common chronic kidney disease. Accumulation of glucose and metabolites activates resident macrophages in kidneys. Resident macrophages play diverse roles on diabetic kidney injuries by releasing cytokines/chemokines, recruiting peripheral monocytes/macrophages, enhancing renal cell injuries (podocytes, mesangial cells, endothelial cells and tubular epithelial cells), and macrophage-myofibroblast transition. The differentiation and cross-talks of macrophages ultimately result renal inflammation and fibrosis in DN. Emerging evidence shows that targeting macrophages by suppressing macrophage activation/transition, and macrophages-cell interactions may be a promising approach to attenuate DN. In the review, we summarized the diverse roles of macrophages and the cross-talks to other cells in DN, and highlighted the therapeutic potentials by targeting macrophages.

Immune responses in diabetic nephropathy: Pathogenic mechanisms and therapeutic target

Diabetic nephropathy (DN) is a chronic, inflammatory disease affecting millions of diabetic patients worldwide. DN is associated with proteinuria and progressive slowing of glomerular filtration, which often leads to end-stage kidney diseases. Due to the complexity of this metabolic disorder and lack of clarity about its pathogenesis, it is often more difficult to diagnose and treat than other kidney diseases. Recent studies have highlighted that the immune system can inadvertently contribute to DN pathogenesis. Cells involved in innate and adaptive immune responses can target the kidney due to increased expression of immune-related localization factors. Immune cells then activate a pro-inflammatory response involving the release of autocrine and paracrine factors, which further amplify inflammation and damage the kidney. Consequently, strategies to treat DN by targeting the immune responses are currently under study. In light of the steady rise in DN incidence, this timely review summarizes the latest findings about the role of the immune system in the pathogenesis of DN and discusses promising preclinical and clinical therapies.

Evaluation of the Therapeutic Effects of Protocatechuic Aldehyde in Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most severe chronic kidney diseases in diabetes and is the main cause of end-stage renal disease (ESRD). Protocatechuic aldehyde (PCA) is a natural product with a variety of effects on pulmonary fibrosis. In this study, we examined the effects of PCA in C57BL/KS db/db male mice. Kidney morphology, renal function indicators, and Western blot, immunohistochemistry, and hematoxylin and eosin (H&E) staining data were analyzed. The results revealed that treatment with PCA could reduce diabetic-induced renal dysfunction, as indicated by the urine albumin-to-creatinine ratio (db/m: 120.1 ± 46.1μg/mg, db/db: 453.8 ± 78.7 µg/mg, db/db + 30 mg/kg PCA: 196.6 ± 52.9 µg/mg, db/db + 60 mg/kg PCA: 163.3 ± 24.6 μg/mg, p < 0.001). However, PCA did not decrease body weight, fasting plasma glucose, or food and water intake in db/db mice. H&E staining data revealed that PCA reduced glomerular size in db/db mice (db/m: 3506.3 ± 789.3 μm², db/db: 6538.5 ± 1818.6 μm², db/db + 30 mg/kg PCA: 4916.9 ± 1149.6 μm², db/db + 60 mg/kg PCA: 4160.4 ± 1186.5 μm²p < 0.001). Western blot and immunohistochemistry staining indicated that PCA restored the normal levels of diabetes-induced fibrosis markers, such as transforming growth factor-beta (TGF-β) and type IV collagen. Similar results were observed for epithelial–mesenchymal transition-related markers, including fibronectin, E-cadherin, and α-smooth muscle actin (α-SMA). PCA also decreased oxidative stress and inflammation in the kidney of db/db mice. This research provides a foundation for using PCA as an alternative therapy for DN in the future.

Divalent Metal Transporter 1 Knock-Down Modulates IL-1β Mediated Pancreatic Beta-Cell Pro-Apoptotic Signaling Pathways through the Autophagic Machinery

Pro-inflammatory cytokines promote cellular iron-import through enhanced divalent metal transporter-1 (DMT1) expression in pancreatic β-cells, consequently cell death. Inhibition of β-cell iron-import by DMT1 silencing protects against apoptosis in animal models of diabetes. However, how alterations of signaling networks contribute to the protective action of DMT1 knock-down is unknown. Here, we performed phosphoproteomics using our sequential enrichment strategy of mRNA, protein, and phosphopeptides, which enabled us to explore the concurrent molecular events in the same set of wildtype and DMT1-silenced β-cells during IL-1β exposure. Our findings reveal new phosphosites in the IL-1β-induced proteins that are clearly reverted by DMT1 silencing towards their steady-state levels. We validated the levels of five novel phosphosites of the potential protective proteins using parallel reaction monitoring. We also confirmed the inactivation of autophagic flux that may be relevant for cell survival induced by DMT1 silencing during IL-1β exposure. Additionally, the potential protective proteins induced by DMT1 silencing were related to insulin secretion that may lead to improving β-cell functions upon exposure to IL-1β. This global profiling has shed light on the signal transduction pathways driving the protection against inflammation-induced cell death in β-cells after DMT1 silencing.

Regulation of Monocytes/Macrophages by the Renin-Angiotensin System in Diabetic Nephropathy: State of the Art and Results of a Pilot Study

Diabetic nephropathy (DN) is characterized by albuminuria, loss of renal function, renal fibrosis and infiltration of macrophages originating from peripheral monocytes inside kidneys. DN is also associated with intrarenal overactivation of the renin-angiotensin system (RAS), an enzymatic cascade which is expressed and controlled at the cell and/or tissue levels. All members of the RAS are present in the kidneys and most of them are also expressed in monocytes/macrophages. This review focuses on the control of monocyte recruitment and the modulation of macrophage polarization by the RAS in the context of DN. The local RAS favors the adhesion of monocytes on renal endothelial cells and increases the production of monocyte chemotactic protein-1 and of osteopontin in tubular cells, driving monocytes into the kidneys. There, proinflammatory cytokines and the RAS promote the differentiation of macrophages into the M1 proinflammatory phenotype, largely contributing to renal lesions of DN. Finally, resolution of the inflammatory process is associated with a phenotype switch of macrophages into the M2 anti-inflammatory subset, which protects against DN. The pharmacologic interruption of the RAS reduces albuminuria, improves the trajectory of the renal function, decreases macrophage infiltration in the kidneys and promotes the switch of the macrophage phenotype from M1 to M2.

Roles of mTOR in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease and the number of patients affected is increasing worldwide. Thus, there is a need to establish a new treatment for DKD to improve the renal prognosis of diabetic patients. Recently, it has shown that intracellular metabolic abnormalities are involved in the pathogenesis of DKD. In particular, the activity of mechanistic target of rapamycin complex 1 (mTORC1), a nutrient-sensing signaling molecule, is hyperactivated in various organs of diabetic patients, which suggests the involvement of excessive mTORC1 activation in the pathogenesis of diabetes. In DKD, hyperactivated mTORC1 may be involved in the pathogenesis of podocyte damage, which causes proteinuria, and tubular cell injury that decreases renal function. Therefore, elucidating the role of mTORC1 in DKD and developing new therapeutic agents that suppress mTORC1 hyperactivity may shed new light on DKD treatments in the future.

Plant Compounds for the Treatment of Diabetes, a Metabolic Disorder: NF-κB as a Therapeutic Target

Background:

The prevalence of diabetes in the world population hás reached 8.8 % and is expected to rise to 10.4% by 2040. Hence, there is an urgent need for the discovery of drugs against therapeutic targets to sojourn its prevalence. Previous studies proved that NF-κB serves as a central agent in the development of diabetic complications.

Objectives:

This review intended to list the natural plant compounds that would act as inhibitors of NF-κB signalling in different organs under the diabetic condition with their possible mechanism of action.

Methods:

Information on NF-κB, diabetes, natural products, and relation in between them, was gathered from scientific literature databases such as Pubmed, Medline, Google scholar, Science Direct, Springer, Wiley online library.

Results and Conclusion:

NF-κB plays a crucial role in the development of diabetic complications because of its link in the expression of genes that are responsible for organs damage such as kidney, brain, eye, liver, heart, muscle, endothelium, adipose tissue and pancreas by inflammation, apoptosis and oxidative stress. Activation of PPAR-α, SIRT3/1, and FXR through many cascades by plant compounds such as terpenoids, iridoids, flavonoids, alkaloids, phenols, tannins, carbohydrates, and phytocannabinoids recovers diabetic complications. These compounds also exhibit the prevention of NF-κB translocation into the nucleus by inhibiting NF-κB activators, such as VEGFR, RAGE and TLR4 receptors, which in turn, prevent the activation of many genes involved in tissue damage. Current knowledge on the treatment of diabetes by targeting NF-κB is limited, so future studies would enlighten accordingly.

Pathogenic Pathways and Therapeutic Approaches Targeting Inflammation in Diabetic Nephropathy

Diabetic nephropathy (DN) is associated with an increased morbidity and mortality, resulting in elevated cost for public health systems. DN is the main cause of chronic kidney disease (CKD) and its incidence increases the number of patients that develop the end-stage renal disease (ESRD). There are growing epidemiological and preclinical evidence about the close relationship between inflammatory response and the occurrence and progression of DN. Several anti-inflammatory strategies targeting specific inflammatory mediators (cell adhesion molecules, chemokines and cytokines) and intracellular signaling pathways have shown beneficial effects in experimental models of DN, decreasing proteinuria and renal lesions. A number of inflammatory molecules have been shown useful to identify diabetic patients at high risk of developing renal complications. In this review, we focus on the key role of inflammation in the genesis and progression of DN, with a special interest in effector molecules and activated intracellular pathways leading to renal damage, as well as a comprehensive update of new therapeutic strategies targeting inflammation to prevent and/or retard renal injury.

Circulating Tumor Necrosis Factor Receptors: A Potential Biomarker for the Progression of Diabetic Kidney Disease

Despite considerable advancements in medicine, the optimal treatment for chronic kidney disease (CKD), especially diabetic kidney disease (DKD), remains a major challenge. More patients with DKD succumb to death due to cardiovascular events than due to progression to end-stage renal disease (ESRD). Moreover, patients with DKD and ESRD have remarkably poor prognosis. Current studies have appreciated the contribution of inflammation and inflammatory mediators, such as tumor necrosis factor (TNF)-related biomarkers, on the development/progression of DKD. The present review focuses on molecular roles, serum concentrations of TNF receptors (TNFRs), and their association with increased albuminuria, eGFR decline, and all-cause mortality in diabetes. Experimental studies have suggested that DKD progression occurs through the TNFα–TNFR2 inflammatory pathway. Moreover, serum TNFR levels were positively associated with albuminuria and negatively associated with estimated glomerular filtration rate (eGFR), while circulating levels of TNFRs exhibited an independent effect on all-cause mortality and eGFR decline, including ESRD, even after adjusting for existing risk factors. However, their precise function has yet to be elucidated and requires further studies.

Intercellular adhesion molecule-1 expression and serum levels as markers of pre-clinical atherosclerosis in polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common reproductive endocrine disorder characterized by obesity, hyperandrogenism, and insulin resistance. Intercellular adhesion molecule-1 (ICAM-1) is a proinflammatory and proatherogenic cytokine which is associated with atherosclerosis, insulin resistance, and cardiovascular disease (CVD). The pathogenesis of PCOS is not precisely known. Thus, the purpose of this study was to investigate the potential role of ICAM-1 expression and serum ICAM-1 concentrations in pathogenesis of PCOS. Moreover, we aimed to evaluate the possible relationship between ICAM-1 gene expression with carotid intima-media thickness as well as clinic-morphological features of PCOS.

METHODS

This case control study enrolled 180 patients with PCOS and 120 controls groups and they were stratified according to their fasting plasma glucose (FPG) into three subgroups; normal glucose tolerance (NGT) [n = 75], those with impaired glucose tolerance (IGT) [n = 65], and 40 patients with type 2 diabetes mellitus (T2DM). Circulating ICAM-1 expression levels were determined by real time polymerase chain reaction (RT-PCR). Serum ICAM-1 concentrations were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Our results revealed that PCOS patients had higher values of ICAM-1expression and serum levels. Among PCOS patients, T2DM patients had the highest values of ICAM-1 expression and serum levels compared to IGT and NGT subgroups. The ICAM-1 expression and serum levels were significantly positive correlated with cardiovascular risk and PCOS phenotypes. Linear regression test showed that HOMA-IR was the main predictors of serum ICAM-1 levels in PCOS. Receiver operating characteristic curve (ROC) analysis revealed that, the power of ICAM-1 expression levels was higher than serum ICAM-1 in diagnosis of PCOS and in differentiating T2DM from IGT and NGT subgroups. Interestingly, combination of both ICAM-1 expression and serum levels improved the diagnostic role of serum ICAM-1.

CONCLUSION

ICAM-1 expression and serum levels were higher in women with PCOS compared to control group also, there was a strong independent association between higher ICAM-1 expression and serum levels with cardiovascular risks in PCOS group.

Intercellular adhesion molecule-1 in diabetic patients with and without microalbuminuria

BACKGROUND

Nephropathy is a major complication of type 2 diabetes mellitus (T2DM) and is heralded by the insidious development of microalbuminuria (MA). It is suggested that the serum levels of Intercellular Adhesion Molecule-1 (ICAM-1) is correlated with diabetic nephropathy. In this cross-sectional study, we evaluated serum ICAM-1 level in diabetic patients with and without MA.

METHODS

A total of 187 participants were enrolled and were classified into three groups including 40 healthy controls and 2 diabetic groups with (n = 59) or without MA (n = 88). Serum levels of ICAM-1, fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, very low density lipoprotein cholesterol and C-reactive protein (CRP) were measured in all three groups. Statistical analyses were performed using the SPSS software. A P-value less than 0.05 was considered statistically significant.

RESULTS

Serum levels of ICAM-1 were significantly higher in diabetic patients irrespective of MA. Moreover, ICAM-1 levels in patients with MA were significantly higher than patients without MA. Patients with MA had significantly higher age and blood pressure compared to those without MA (P = 0.001). Serum levels of ICAM-1 were significantly correlated with age and HbA1c.

CONCLUSIONS

Overall, serum ICAM-1 levels were significantly higher in T2DM patients with MA and it may be associated with the severity of diabetic kidney disease.

Quercetin nanoparticle complex attenuated diabetic nephropathy via regulating the expression level of ICAM-1 on endothelium

The purpose of the study was to reveal the therapeutic effect of quercetin (QUE) nanoparticle complex on diabetic nephropathy (DN) by regulating the expression of intercellular adhesion molecular-1 (ICAM-1) on endothelium as compared to free QUE. QUE 10 mg/kg as a single abdominal subcutaneous injection daily for 8 weeks continuously in diabetic rats and 10 mg/kg QUE nanoparticle complex as a single abdominal subcutaneous injection every 5 days, continuously administered for 8 weeks to diabetic rats. Blood and left kidneys were collected; pathological change of kidney, renal function, oxidative stress level, blood glucose level, serum lipid, urine protein, and albumin/creatinine ratio were measured; and neutrophil adhesion, ICAM-1 expression, and CD11b⁺ cells infiltration were observed. Both QUE and QUE nanoparticle complex preconditioning ameliorated the pathological damage of kidney and improved renal function, alleviated renal oxidative stress injury, restricted inflammatory cells infiltration, and downregulated the ICAM-1 expression as compared to DN group, while QUE nanoparticle complex significantly alleviated this effect.

Calcium dobesilate may alleviate diabetes‑induced endothelial dysfunction and inflammation

Diabetic kidney disease (DKD) is a leading cause of end‑stage renal disease. However, the pathogenesis of DKD remains unclear, and no effective treatments for the disease are available. Thus, there is an urgent need to elucidate the pathogenic mechanisms of DKD and to develop more effective therapies for this disease. Human umbilical vein endothelial cells (HUVECs) were cultured using different D‑glucose concentrations to determine the effect of high glucose (HG) on the cells. Alternatively, HUVECs were incubated with 100 µmol/l calcium dobesilate (CaD) to detect its effects. The authors subsequently measured HUVEC proliferation via cell counting kit‑8 assays. In addition, HUVEC angiogenesis was investigated via migration assays and fluorescein isothiocyanate (FITC)‑labelled bovine serum albumin (BSA) permeability assays. The content or distribution of markers of endothelial dysfunction [vascular endothelial growth factor (VEGF), VEGF receptor (R) and endocan) or inflammation [intercellular adhesion molecule (ICAM)‑1, monocyte chemotactic protein (MCP)‑1 and pentraxin‑related protein (PTX3)] was evaluated via reverse transcription‑quantitative polymerase chain reaction and western blotting. HG treatment induced increased in VEGF, VEGFR, endocan, ICAM‑1, MCP‑1 and PTX3 mRNA and protein expression in HUVECs. HG treatment for 24 to 48 h increased cell proliferation in a time‑dependent manner, but the cell proliferation rate was decreased at 72 h of HG treatment. Conversely, CaD inhibited abnormal cell proliferation. HG treatment also significantly enhanced HVUEC migration compared to the control treatment. In contrast, CaD treatment partially inhibited HUVEC migration compared to HG exposure. HG‑treated HUVECs exhibited increased FITC‑BSA permeability compared to control cells cultured in medium alone; however, CaD application prevented the HG‑induced increase in FITC‑BSA permeability and suppressed HG‑induced overexpression of endothelial markers (VEGF, VEGFR‑2, endocan) and inflammation markers (ICAM‑1, MCP‑1, PTX3) in HUVECs. CaD has angioprotective properties and protects endothelial cells partly by ameliorating HG‑induced inflammation. The current results demonstrated the potential applicability of CaD to the treatment of diabetic nephropathy, particularly during the early stages of this disease.

High glucose induces HGF-independent activation of Met receptor in human renal tubular epithelium

CONTEXT

The role of hepatocyte growth factor (HGF) in diabetic kidney damage remains controversial.

OBJECTIVE

To test the hypothesis that high glucose levels activate pathways related to HGF and its receptor Met and that this could participate in glucose-induced renal cell damage.

MATERIALS AND METHODS

HK2 cells, a human proximal tubule epithelial cell line, were stimulated with high glucose for 48 hours. Levels of pMet/Met, pEGFR/EGFR, pSTAT3/STAT3, pAkt/Akt and pERK1/2/ERK1/2 were studied by immunoblotting. Absence of HGF was verified by qRT-PCR and ELISA.

RESULTS

High glucose level activated Met and its downstream pathways STAT3, Akt and ERK independently of HGF. High glucose induced an integrin ligand fibronectin. HGF-independent Met phosphorylation was prevented by inhibition of integrin α5β1, Met inhibitor crizotinib, Src inhibitors PP2 and SU5565, but not by EGFR inhibitor AG1478. High glucose increased the expression of TGFβ-1, CTGF and the tubular damage marker KIM-1 and increased apoptosis of HK2 cells, effects inhibited by crizotinib.

CONCLUSION

High glucose activated Met receptor in HK2 cells independently of HGF, via induction of integrin α5β1 and downstream signaling. This mode of Met activation was associated with tubular cell damage and apoptosis and it may represent a novel pathogenic mechanism and a treatment target in diabetic nephropathy.

Immunity and inflammation in diabetic kidney disease: translating mechanisms to biomarkers and treatment targets

Increasing incidences of obesity and diabetes have made diabetic kidney disease (DKD) the leading cause of chronic kidney disease and end-stage renal disease worldwide. Despite current pharmacological treatments, including strategies for optimizing glycemic control and inhibitors of the renin-angiotensin system, DKD still makes up almost one-half of all cases of end-stage renal disease in the United States. Compelling and mounting evidence has clearly demonstrated that immunity and inflammation play a paramount role in the pathogenesis of DKD. This article reviews the involvement of the immune system in DKD and identifies important roles of key immune and inflammatory mediators. One of the most recently identified biomarkers is serum amyloid A, which appears to be relatively specific for DKD. Novel and evolving treatment approaches target protein kinases, transcription factors, chemokines, adhesion molecules, growth factors, advanced glycation end-products, and other inflammatory molecules. This is the beginning of a new era in the understanding and treatment of DKD, and we may have finally reached a tipping point in our fight against the growing burden of DKD.

Diabetes-Induced Reactive Oxygen Species: Mechanism of Their Generation and Role in Renal Injury

Diabetes induces the onset and progression of renal injury through causing hemodynamic dysregulation along with abnormal morphological and functional nephron changes. The most important event that precedes renal injury is an increase in permeability of plasma proteins such as albumin through a damaged glomerular filtration barrier resulting in excessive urinary albumin excretion (UAE). Moreover, once enhanced UAE begins, it may advance renal injury from progression of abnormal renal hemodynamics, increased glomerular basement membrane (GBM) thickness, mesangial expansion, extracellular matrix accumulation, and glomerulosclerosis to eventual end-stage renal damage. Interestingly, all these pathological changes are predominantly driven by diabetes-induced reactive oxygen species (ROS) and abnormal downstream signaling molecules. In diabetic kidney, NADPH oxidase (enzymatic) and mitochondrial electron transport chain (nonenzymatic) are the prominent sources of ROS, which are believed to cause the onset of albuminuria followed by progression to renal damage through podocyte depletion. Chronic hyperglycemia and consequent ROS production can trigger abnormal signaling pathways involving diverse signaling mediators such as transcription factors, inflammatory cytokines, chemokines, and vasoactive substances. Persistently, increased expression and activation of these signaling molecules contribute to the irreversible functional and structural changes in the kidney resulting in critically decreased glomerular filtration rate leading to eventual renal failure.

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.

Inhibition of T-cell activation by the CTLA4-Fc Abatacept is sufficient to ameliorate proteinuric kidney disease

Diabetic nephropathy (DN) remains an unmet medical challenge as its prevalence is projected to continue to increase and specific medicines for treatment remain undeveloped. Activation of the immune system, in particular T-cells, is emerging as a possible mechanism underlying DN disease progression in humans and animal models. We hypothesized that inhibition of T-cell activation will ameliorate DN. Interaction of B7-1 (CD80) on the surface of antigen presenting cells with its binding partners, CTLA4 (CD152) and CD28 on T-cells, is essential for T-cell activation. In this study we used the soluble CTLA4-Fc fusion protein Abatacept to block cell surface B7-1, preventing the cellular interaction and inhibiting T-cell activation. When Abatacept was dosed in an animal model of diabetes-induced albuminuria, it reduced albuminuria in both prevention and intervention modes. The number of T-cells infiltrating the kidneys of DN animals correlated with the degree of albuminuria, and treatment with Abatacept reduced the number of renal T-cells. As B7-1 induction has been recently proposed to underlie podocyte damage in DN, Abatacept could be efficacious in DN by protecting podocytes. However, this does not appear to be the case as B7-1 was not expressed in 1) kidneys of DN animals; 2) stimulated human podocytes in culture; or 3) glomeruli of DN patients. We conclude that Abatacept ameliorates DN by blocking systemic T-cell activation and not by interacting with podocytes.

Polydatin attenuates AGEs-induced upregulation of fibronectin and ICAM-1 in rat glomerular mesangial cells and db/db diabetic mice kidneys by inhibiting the activation of the SphK1-S1P signaling pathway

We previously demonstrated that activation of sphingosine kinase 1 (SphK1)- sphingosine 1- phosphate (S1P) signaling pathway by high glucose (HG) plays a pivotal role in increasing the expression of fibronectin (FN), an important fibrotic component, by promoting the DNA-binding activity of transcription factor activator protein 1 (AP-1) in glomerular mesangial cells (GMCs) under diabetic conditions. As a multi-target anti-oxidative drug, polydatin (PD) has been shown to have renoprotective effects on experimental diabetes. However, whether PD could resist diabetic nephropathy (DN) by regulating SphK1-S1P signaling pathway needs further investigation. Here, we found that PD significantly reversed the upregulated FN and ICAM-1 expression in GMCs exposed to AGEs. Simultaneously, PD dose-dependently inhibited SphK1 levels at the protein expression and kinase activity and attenuated S1P production under AGEs treatment conditions. In addition, PD reduced SphK activity in GMCs transfected with wild-type SphK(WT) plasmid and significantly suppressed SphK1-mediated increase of FN and ICAM-1 levels under normal conditions. Furthermore, we found that the AGEs-induced upregulation of phosphorylation of c-Jun at Ser63 and Ser73 and c-Fos at Ser32, DNA-binding activity and transcriptional activity of AP-1 were blocked by PD. In comparison with db/db model group, PD treatment suppressed SphK1 levels (mRNA, protein expression, and activity) and S1P production, reversed the upregulation of FN, ICAM-1, c-Jun, and c-Fos in the kidney tissues of diabetic mice, and finally ameliorated renal injury in db/db mice. These findings suggested that the downregulation of SphK1-S1P signaling pathway is probably a novel mechanism by which PD suppressed AGEs-induced FN and ICAM-1 expression and improved renal dysfunction of diabetic models.

No Additional Effect of DPP-4 Inhibitor on Preventing Atrial Fibrosis in Streptozotocin-Induced Diabetic Rat as Compared With Sulfonylurea

Chronic inflammation is known to occur in diabetes mellitus (DM) and contributes to atrial fibrosis, possible substrates for atrial fibrillation. We tested the hypothesis that dipeptidyl peptidase (DPP)-4 inhibitors prevent the formation of atrial fibrosis through their anti-inflammatory activity, beyond the effects of controlling blood glucose.DM models obtained by administration of streptozotocin (STZ) were divided into 3 groups: with PKF275-055, a DPP-4 inhibitor in group D, glibenclamide in group SU, and no additional drug in group P. At 8 weeks after STZ administration, the heart was subjected to Masson trichrome staining and immunohistochemistry with anti-ED2, ED3, and smooth muscle actin antibody.The % area of fibrosis in atria of group P accounted for 14.7% ± 4.1%, showing a significant increase in fibrosis when compared with the control group. In group SU, the % area accounted for 7.9% ± 2.9%, indicating significant deceased fibrosis by sulfonylurea. Meanwhile, we could not find significant differences in group D when compared to group P or group SU. While ED3-positive cells increased in group P (1.12% ± 0.24%), they were significantly decreased in groups D and SU (0.41% ± 0.22% and 0.55% ± 0.29%, respectively). Between group D and SU, however, there were no significant differences in the amount of cells positive to ED2, ED3, and smooth muscle actin antibodies.In STZ-induced DM rats, administration of sulfonylurea and DPP-4 inhibitors inhibited inflammation and fibrosis of the atria. However, no significant differences were observed between the 2 antidiabetic drugs.

Association of ICAM-1 (K469E) and MCP-1 -2518 A>G gene polymorphism with brain abscess

Brain abscess develops in response to a parenchymal infection. Intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) play vital role in central nervous system (CNS) diseases. We studied ICAM-1 (K469E) and MCP-1 (-2518 A>G) polymorphisms among brain abscess patients. The genotypic distributions of ICAM-1 (K469E) and MCP-1 (-2518 A>G) were significantly different between patients and controls. Further, patient with predisposing factors, and also with culture result, we found significant association. The study revealed that the polymorphisms of these molecules lead to increased production, which appears to be a risk for the development of brain abscess.

New molecular insights in diabetic nephropathy

Diabetes mellitus represents one of the major causes of functional kidney impairment. The review highlights the most significant steps made over the last decades in understanding the molecular basis of diabetic nephropathy (DN), which may provide reliable biomarkers for early diagnosis and prognosis, along with new molecular targets for personalized medicine. There is an increased interest in developing new therapeutic strategies to slow DN progression for improving patients' quality of life and reducing all-cause morbidity and disease-associated mortality. It is highly important to have a science-based medical attitude when facing diabetic patients with associated comorbidities and risk of rapid evolution toward end-stage renal disease. The data discussed herein were mainly from MEDLINE and PubMed articles published in English from 1990 to 2015 and from up-to-date. The search term was "diabetic nephropathy and oxidative stress".

Human endothelial colony-forming cells protect against acute kidney injury: role of exosomes

The administration of certain progenitor cells is protective in experimental acute kidney injury (AKI), and mechanisms may involve the release of paracrine factors. Endothelial colony-forming cells (ECFCs) are endothelial precursor cells with a high proliferative capacity and pro-angiogenic potential. We examined the effects of human umbilical cord blood-derived ECFCs and their extracellular vesicles in a mouse model of ischemic AKI and in cultured human umbilical vein endothelial cells subjected to hypoxia/reoxygenation. In mice with ischemic AKI, administration of ECFCs (i.v.) at the time of reperfusion significantly attenuated increases in plasma creatinine, tubular necrosis, macrophage infiltration, oxidative stress, and apoptosis, without cell persistence in the kidneys. In cultured human umbilical vein endothelial cells, hypoxia/reoxygenation stimulated apoptosis. This effect was inhibited by incubation with conditioned medium or exosomes (40- to 100-nm diameter) derived from ECFCs, but not by microparticles (100- to 1000-nm diameter) or vesicle-depleted conditioned medium. Administration of exosomes (i.v.) directly to mice with ischemic AKI attenuated renal injury, as assessed by plasma creatinine, tubular necrosis, and apoptosis. Taken together, these studies indicate protective effects of human cord blood-derived ECFCs in experimental AKI and suggest that ECFC-derived exosomes may mediate the protective response via inhibition of endothelial cell apoptosis.

Dipeptidyl peptidase-4 deficiency protects against experimental diabetic nephropathy partly by blocking the advanced glycation end products-receptor axis

Advanced glycation end products (AGEs) and their receptor (RAGE) have a role in diabetic nephropathy. We have recently found that linagliptin, an inhibitor of dipeptidyl peptidase-4 (DPP-4), could inhibit renal damage in type 1 diabetic rats by suppressing the AGE-RAGE axis. However, it remains unclear whether DPP-4 deficiency could also have beneficial effects on experimental diabetic nephropathy. To address the issue, we rendered wild-type F344/NSlc and DPP-4-deficient F344/DuCrl/Crlj rats diabetic by injection of streptozotocin, and then investigated whether DPP-4 deficiency could block the activation of AGE-RAGE axis in the diabetic kidneys and resultantly ameliorate renal injury in streptozotocin-induced diabetic rats. Compared with control rats at 9 and 11 weeks old, body weight and heart rates were significantly lower, while fasting blood glucose was higher in wild-type and DPP-4-deficient diabetic rats at the same age. There was no significant difference of body weight, fasting blood glucose and lipid parameters between the two diabetic rat strains. AGEs, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and nitrotyrosine levels in the kidney, renal gene expression of RAGE and intercellular adhesion molecule-1, glomerular area, urinary excretion of 8-OHdG and albumin, and the ratio of renal to body weight were increased in wild-type diabetic rats at 9 and/or 11 weeks old compared with age-matched control rats, all of which except for urinary 8-OHdG levels at 11 weeks old were significantly suppressed in DPP-4-deficient diabetic rats. Our present study suggests that DPP-4 deficiency could exert beneficial actions on type 1 diabetic nephropathy partly by blocking the AGE-RAGE axis. DPP-4 might be a novel therapeutic target for preventing diabetic nephropathy.

Inflammation in diabetic nephropathy: moving toward clinical biomarkers and targets for treatment

Diabetic nephropathy (DN) is a leading cause of end stage renal failure and there is an urgent need to identify new clinical biomarkers and targets for treatment to effectively prevent and slow the progression of the complication. Many lines of evidence show that inflammation is a cardinal pathogenetic mechanism in DN. Studies in animal models of experimental diabetes have demonstrated that there is a low-grade inflammation in the diabetic kidney. Both pharmacological and genetic strategies targeting inflammatory molecules have been shown to be beneficial in experimental DN. In vitro studies have cast light on the cellular mechanisms whereby diabetes triggers inflammation and in turn inflammation magnifies the kidney injury. Translation of this basic science knowledge into potential practical clinical applications is matter of great interest for researchers today. This review focuses on key pro-inflammatory systems implicated in the development of DN: the tumor necrosis factor(TNF)-α/TNF-α receptor system, the monocyte chemoattractant protein-1/CC-chemokine receptor-2 system, and the Endocannabinoid system that have been selected as they appear particularly promising for future clinical applications.

Markers of endothelial dysfunction and inflammation predict progression of diabetic nephropathy in African Americans with type 1 diabetes

African Americans with early-onset type 1 diabetes mellitus are at a high risk for severe diabetic nephropathy and end-stage renal disease. In order to determine whether baseline plasma levels of inflammatory markers predict incidence of overt proteinuria or renal failure in African Americans with type 1 diabetes mellitus, we re-examined data of 356 participants in our observational follow-up study of 725 New Jersey African Americans with type 1 diabetes. At baseline and 6-year follow-up, a detailed structured clinical interview was conducted to document medical history including kidney dialysis or transplant, other diabetic complications, and renal-specific mortality. Plasma levels of 28 inflammatory biomarkers were measured using a multiplex bead analysis system. After adjusting for baseline age, glycohemoglobin, and other confounders, the baseline plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) in the upper two quartiles were, respectively, associated with a three- to fivefold increase in the risk of progression from no albuminuria or microalbuminuria to overt proteinuria. Baseline plasma levels of the chemokine eotaxin in the upper quartile were significantly associated with a sevenfold increase in risk of incident renal failure. These associations were independent of traditional risk factors for progression of diabetic nephropathy. Thus, in type 1 diabetic African Americans, sICAM-1 predicted progression to overt proteinuria and eotaxin-predicted progression to renal failure.

Exendin-4 attenuates renal tubular injury by decreasing oxidative stress and inflammation in streptozotocin-induced diabetic mice

In this study, we aimed to research the restorative effects of exendin-4, a GLP-1 analog, on renal tubular injury in streptozotocin-induced diabetes model. BALB/c male mice were divided into four groups: non-diabetic, non-diabetic + exendin-4 (3 μg/kg), diabetic and diabetic + exendin-4. In our diabetic model, we observed renal injury mainly in tubular area rather than glomeruli and exendin-4 decreased tubular injury with its glucose lowering effect. Besides, PCNA positive tubular cells, activities of LDH and Na(+)-K(+)-ATPase were also significantly declined by the administration of exendin-4. Furthermore, exendin-4 attenuated the levels of ROS, MDA, 8-OHdG, proinflammatory cytokines (TNF-α, IL-1β), chemokine MCP-1, ICAM-1, and fibrosis-related molecules (transforming growth factor β1 and fibronectin). In consistent with reducing tubular injury, macrophage infiltration and both MCP-1 and ICAM-1 production in tubular cells were decreased. These results indicate that exendin-4 may decrease renal tubular injury seen in the beginning of diabetic nephropathy by decreasing ROS production and inflammation.

Liraglutide inhibits autophagy and apoptosis induced by high glucose through GLP-1R in renal tubular epithelial cells

Tubular atrophy and dysfunction is a critical process underlying diabetic nephropathy (DN). Understanding the mechanisms underlying renal tubular epithelial cell survival is important for the prevention of kidney failure associated with glucotoxicity. Autophagy is a cellular pathway involved in protein and organelle degradation. It is associated with many types of cellular homeostasis and human diseases. To date, little is known of the association between high concentrations of glucose and autophagy in renal tubular cells. In the present study, we investigated high glucose-induced toxicity in renal tubular epithelial cells by means of several complementary assays, including cell viability, cell death assays and changes in ultrastructure in an immortalized human kidney cell line, HK-2 cells. The extent of apoptosis was significantly increased in the HK-2 cells following treatment with high levels of glucose. In addition, in in vivo experiments using diabetic rats, high glucose exerted harmful effects on the tissue structure of the kidneys in the diabetic rats. Chronic exposure of the HK-2 cells and tubular epithelial cells of nephritic rats to high levels of glucose induced autophagy. Liraglutide inhibited these effects; however, treatment witht a glucagon-like peptide-1 receptor (GLP-1R) antagonist enhanced these effects. Our results also indicated that the exposure of the renal tubular epithelial cells to high glucose concentrations in vitro led to the downregulation of GLP-1R expression. Liraglutide reversed this effect, while the GLP-1R antagonist promoted it, promoting autophagy, suggesting that liraglutide exerts a renoprotective effect in the presence of high glucose, at least in part, by inhibiting autophagy and increasing GLP-1R expression in the HK-2 cells and kidneys of diabetic rats.

Microinflammation in the pathogenesis of diabetic nephropathy

Diabetic nephropathy is the leading cause of end‐stage renal failure in developed countries. Furthermore, diabetic nephropathy is related to the risk of cardiovascular diseases and an increase in mortality of diabetic patients. Several factors are involved in the development of nephropathy, including glomerular hyperfiltration, oxidative stress, accumulation of advanced glycation end‐products, activation of protein kinase C, acceleration of the polyol pathway and over‐expression of transforming growth factor‐β. Recently, accumulated data have emphasized the critical roles of chronic low‐grade inflammation, ‘microinflammation’, in the pathogenesis of diabetic nephropathy, suggesting that microinflammation is a common mechanism in the development of diabetic vascular complications. Expression of cell adhesion molecules, chemokines and pro‐inflammatory cytokines are increased in the renal tissues of diabetic patients and animals. Deficiency of pro‐inflammatory molecules results in amelioration of renal injuries after induction of diabetes in mice. Plasma and urinary levels of cytokines, chemokines and cell adhesion molecules, are elevated and correlated with albuminuria. Several kinds of drugs that have anti‐inflammatory actions as their pleiotropic effects showed renoprotective effects on diabetic animals. Modulation of the inflammatory process prevents renal insufficiency in diabetic animal models, suggesting that microinflammation is one of the promising therapeutic targets for diabetic nephropathy, as well as for cardiovascular diseases.

Therapeutic approaches to diabetic nephropathy--beyond the RAS

Despite improvements in glycaemic and blood pressure control, and the efficacy of renin-angiotensin system (RAS) blockade for proteinuria reduction, diabetic nephropathy is the most frequent cause of end-stage renal disease in developed countries. This finding is consistent with the hypothesis that key pathogenetic mechanisms leading to progression of renal disease are not modified or inactivated by current therapeutic approaches. Although extensive research has elucidated molecular signalling mechanisms that are involved in progression of diabetic kidney disease, a number of high-profile clinical trials of potentially nephroprotective agents have failed, highlighting an insufficient understanding of pathogenic pathways. These include trials of paricalcitol in early diabetic kidney disease and bardoxolone methyl in advanced-stage disease. Various strategies based on encouraging data from preclinical studies that showed renoprotective effects of receptor antagonists, neutralizing antibodies, kinase inhibitors, small compounds and peptide-based technologies are currently been tested in randomized controlled trials. Phase II clinical trials are investigating approaches targeting inflammation, fibrosis and signalling pathways. However, only one trial that aims to provide evidence for marketing approval of a potentially renoprotective drug (atrasentan) is underway-further research into the potential nephroprotective effects of novel glucose-lowering agents is required.

Endothelin antagonists for diabetic and non-diabetic chronic kidney disease

Numerous pre-clinical studies have implicated endothelin-1 in the pathogenesis of diabetic and non-diabetic chronic kidney disease (CKD). Renal endothelin-1 production is almost universally increased in kidney disease. The pathologic effects of endothelin-1, including vasoconstriction, proteinuria, inflammation, cellular injury and fibrosis, are likely mediated by the endothelin A (ETA) receptor. ETA antagonism alone, and/or combined ETA/B blockade, reduces CKD progression. Based on the strong pre-clinical data, several clinical trials using ETA antagonists were conducted. Small trials involving acute intravenous endothelin receptor blockade suggest that ETA, but not ETB, blockade exerts protective renal and vascular effects in CKD patients. A large phase 3 trial (ASCEND) examined the effects of avosentan, an endothelin receptor antagonist, on renal disease progression in diabetic nephropathy. Proteinuria was reduced after 3-6 months of treatment. However the study was terminated due to increased morbidity and mortality associated with avosentan-induced fluid retention. Several phase 2 trials using avosentan at lower doses than in ASCEND, atrasentan or sitaxsentan (the latter two being highly ETA-selective) showed reductions in proteinuria on top of renin-angiotensin system blockade. Infrequent and clinically insignificant fluid retention was observed at the most effective doses. Additional trials using ETA blockers are ongoing or being planned in patients with diabetic nephropathy or focal segmental glomerulosclerosis. Moving forward, such studies must be conducted with careful patient selection and attention to dosing in order to minimize adverse side effects. Nonetheless, there is cause for optimism that this class of agents will ultimately prove to be effective for the treatment of CKD.

Dipeptidyl peptidase-4 inhibitor ameliorates early renal injury through its anti-inflammatory action in a rat model of type 1 diabetes

INTRODUCTION

Dipeptidyl peptidase-4 (DPP-4) inhibitors are incretin-based drugs in patients with type 2 diabetes. In our previous study, we showed that glucagon-like peptide-1 (GLP-1) receptor agonist has reno-protective effects through anti-inflammatory action. The mechanism of action of DPP-4 inhibitor is different from that of GLP-1 receptor agonists. It is not obvious whether DPP-4 inhibitor prevents the exacerbation of diabetic nephropathy through anti-inflammatory effects besides lowering blood glucose or not. The purpose of this study is to clarify the reno-protective effects of DPP-4 inhibitor through anti-inflammatory actions in the early diabetic nephropathy.

MATERIALS AND METHODS

Five-week-old male Sprague-Dawley (SD) rats were divided into three groups; non-diabetes, diabetes and diabetes treated with DPP-4 inhibitor (PKF275-055; 3 mg/kg/day). PKF275-055 was administered orally for 8 weeks.

RESULTS

PKF275-055 increased the serum active GLP-1 concentration and the production of urinary cyclic AMP. PKF275-055 decreased urinary albumin excretion and ameliorated histological change of diabetic nephropathy. Macrophage infiltration was inhibited, and inflammatory molecules were down-regulated by PKF275-055 in the glomeruli. In addition, nuclear factor-κB (NF-κB) activity was suppressed in the kidney.

CONCLUSIONS

These results indicate that DPP-4 inhibitor, PKF275-055, have reno-protective effects through anti-inflammatory action in the early stage of diabetic nephropathy. The endogenous biological active GLP-1 might be beneficial on diabetic nephropathy besides lowering blood glucose.

Targeting JNK by a new curcumin analog to inhibit NF-kB-mediated expression of cell adhesion molecules attenuates renal macrophage infiltration and injury in diabetic mice

Macrophage infiltration contributes to the pathogenesis of diabetic renal injury. However, the regulatory mechanisms between macrophage infiltration and epithelial cell activation are still unclear. Our previous study found that C66, a novel curcumin analog, was able to inhibit inflammatory cytokine expression in vitro and in vivo. This study further elucidated whether C66 can prevent glucose-induced renal epithelial activation and inflammatory macrophage infiltration by a MAPK/NF-κB medicated mechanism. Our data show that pretreatment with C66 not only significantly reduced high glucose (HG)-induced over-expressions of VCAM-1, ICAM-1 and MCP-1, but also remarkably inhibited NF-κB activation, MAPKs phosphorylation, and subsequently macrophage adhesion in renal epithelial NRK-52E cells. Furthermore, we find that MAPKs, especially JNK, play important roles in HG-induced NF-κB activation, which regulates the over-expression of adhesion molecules in HG-stimulated NRK-52E cells. A molecular docking predicted that C66 may target JNK2, which leads to its anti-inflammatory actions. In vivo, administration of C66 or JNK special inhibitor SP600125 at 5 mg/kg markedly decreased diabetes-induced renal adhesion molecule expression, NF-κB activation, inflammatory cell infiltration, and pathological indexes in the kidneys of diabetic mice. These findings provide a perspective on the renoprotective effects of C66 in diabetes, and outline a novel therapeutic strategy of JNK inhibition for the treatment of diabetic nephropathy.

Development of aldose reductase inhibitors for the treatment of inflammatory disorders

INTRODUCTION

Accumulating evidence attributes a significant role to aldose reductase (ALR2) in the pathogenesis of several inflammatory pathologies. Aldose reductase inhibitors (ARIs) were found to attenuate reactive oxygen species (ROS) production both in vitro and in vivo. Thus, they disrupt signaling cascades that lead to the production of cytokines/chemokines, which induce and exacerbate inflammation. As a result, ARIs might hold a significant therapeutic potential as alternate anti-inflammatory drugs.

AREAS COVERED

The authors present a comprehensive review of the current data that support the central role of ALR2 in several inflammatory pathologies (i.e., diabetes, cancer, sepsis, asthma and ocular inflammation). Further, the authors describe the potential underlying molecular mechanisms and provide a commentary on the status of ARIs in this field.

EXPERT OPINION

It is important that future efforts focus on delineating all the steps of the molecular mechanism that implicates ALR2 in inflammatory pathologies. At the same time, utilizing the previous efforts in the field of ARIs, several candidates that have been proven safe in the clinic may be evaluated for their clinical significance as anti-inflammatory medication. Finally, structurally novel ARIs, designed to target specifically the proinflammatory subpocket of ALR2, should be pursued.

An Aqueous-Ethanol Extract of Liriope spicata var. prolifera Ameliorates Diabetic Nephropathy through Suppression of Renal Inflammation

The tuberous root of Liriope spicata var. prolifera (TRLS; Liliaceae family) is valued for the ability to promote glucose homeostasis, and it may therefore be utilized as an adjuvant therapy in the control of diabetic complications. The aim of the present study was to examine the effects of an aqueous ethanol extract from TRLS (TRLS-ext) (100 or 200 mg kg⁻¹ per day for eight weeks) on rats with streptozotocin-induced diabetic nephropathy (DN). Renal dysfunction in diabetic rats was ameliorated by TRLS-ext as evidenced by reduced creatinine clearance, as well as increased blood urea nitrogen and proteinuria. Treatment with TRLS-ext was found to markedly improve histological architecture in the diabetic kidney. Hyperglycemia induced degradation of inhibitory kappa B and reduced nuclear factor kappa B activation, leading to increased infiltration of macrophages and increased levels of proinflammatory cytokines, including interleukin-1 and tumor necrosis factor-α. All of the above abnormalities were reversed by TRLS-ext treatment, which also decreased the expression of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, and fibronectin in the diabetic kidneys. These findings provide a perspective on the renoprotective effects of TRLS-ext in DN.

[Rheumatoid arthritis. Systemic inflammation and cardiovascular morbidity]

In recent years it could be shown that systemic inflammation, which typically occurs in chronic inflammatory rheumatic diseases, significantly contributes to cardiovascular morbidity and mortality. All rheumatic diseases inherit this enhanced risk for cardiovascular complications with rheumatoid arthritis being one of the most prominent. As the underlying pathophysiological mechanisms are very similar with respect to endothelial damage all rheumatic diseases and specifically rheumatoid arthritis should be monitored and treated with disease-modifying drugs and biological agents as consistently as possible to be able to improve the long-term outcome of affected patients as much as possible.

Astragaloside IV ameliorates renal injury in streptozotocin-induced diabetic rats through inhibiting NF-κB-mediated inflammatory genes expression

Accumulating evidence suggests that inflammatory processes are involved in the development of diabetic nephropathy (DN). However, there are no effective interventions for inflammation in the diabetic kidneys. Here, we tested the hypothesis that Astragaloside IV(AS-IV), a novel saponin purified from Astragalus membranaceus (Fisch) Bge, ameliorates DN in streptozotocin (STZ)-induced diabetic rats through anti-inflammatory mechanisms. Diabetes was induced with STZ (65 mg/kg) by intraperitoneal injection in rats. Two weeks after STZ injection, rats were divided into three groups (n=8/each group), namely, diabetic rats, diabetic rats treated with AS-IV at 5 and 10 mgkg(-1)d(-1), p.o., for 8 weeks. The normal rats were chosen as nondiabetic control group (n=8). The rats were sacrificed 10 weeks after induction of diabetes. AS-IV ameliorated albuminuria, renal histopathology and podocyte foot process effacement in diabetic rats. Renal NF-κB activity, as wells as protein and mRNA expression were increased in diabetic kidneys, accompanied by an increase in mRNA expression and protein content of TNF-α, MCP-1 and ICAM-1 in kidney tissues. The α1-chain type IV collagen mRNA was elevated in the kidneys of diabetic rats. All of these abnormalities were partially restored by AS-IV. AS-IV also decreased the serum levels of TNF-α, MCP-1 and ICAM-1 in diabetic rats. These findings suggest that AS-IV, a novel anti-inflammatory agent, attenuated DN in rats through inhibiting NF-κB mediated inflammatory genes expression.

Matching experiments across species using expression values and textual information

Motivation: With the vast increase in the number of gene expression datasets deposited in public databases, novel techniques are required to analyze and mine this wealth of data. Similar to the way BLAST enables cross-species comparison of sequence data, tools that enable cross-species expression comparison will allow us to better utilize these datasets: cross-species expression comparison enables us to address questions in evolution and development, and further allows the identification of disease-related genes and pathways that play similar roles in humans and model organisms. Unlike sequence, which is static, expression data changes over time and under different conditions. Thus, a prerequisite for performing cross-species analysis is the ability to match experiments across species.

Results: To enable better cross-species comparisons, we developed methods for automatically identifying pairs of similar expression datasets across species. Our method uses a co-training algorithm to combine a model of expression similarity with a model of the text which accompanies the expression experiments. The co-training method outperforms previous methods based on expression similarity alone. Using expert analysis, we show that the new matches identified by our method indeed capture biological similarities across species. We then use the matched expression pairs between human and mouse to recover known and novel cycling genes as well as to identify genes with possible involvement in diabetes. By providing the ability to identify novel candidate genes in model organisms, our method opens the door to new models for studying diseases.

Availability: Source code and supplementary information is available at: www.andrew.cmu.edu/user/aaronwis/cotrain12.

Contact:zivbj@cs.cmu.edu

Supplementary information:Supplementary data are available at Bioinformatics online.

Inflammation and the pathogenesis of diabetic nephropathy

The most problematic issue in clinical nephrology is the relentless and progressive increase in patients with ESRD (end-stage renal disease) worldwide. The impact of diabetic nephropathy on the increasing population with CKD (chronic kidney disease) and ESRD is enormous. Three major pathways showing abnormality of intracellular metabolism have been identified in the development of diabetic nephropathy: (i) the activation of polyol and PKC (protein kinase C) pathways; (ii) the formation of advanced glycation end-products; and (iii) intraglomerular hypertension induced by glomerular hyperfiltration. Upstream of these three major pathways, hyperglycaemia is the major driving force of the progression to ESRD from diabetic nephropathy. Downstream of the three pathways, microinflammation and subsequent extracellular matrix expansion are common pathways for the progression of diabetic nephropathy. In recent years, many researchers have been convinced that the inflammation pathways play central roles in the progression of diabetic nephropathy, and the identification of new inflammatory molecules may link to the development of new therapeutic strategies. Various molecules related to the inflammation pathways in diabetic nephropathy include transcription factors, pro-inflammatory cytokines, chemokines, adhesion molecules, Toll-like receptors, adipokines and nuclear receptors, which are candidates for the new molecular targets for the treatment of diabetic nephropathy. Understanding of these molecular pathways of inflammation would translate into the development of anti-inflammation therapeutic strategies.